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87 Hiroshima Essay Topic Ideas & Examples

🏆 best hiroshima topic ideas & essay examples, 📌 simple & easy hiroshima essay titles, 👍 good essay topics on hiroshima, ❓ hiroshima essay questions.

• Hiroshima: Rising from the Ashes of Nuclear Destruction After a few years, the city of han was abolished and Hiroshima became the capital city of the whole Hiroshima region.
• Hiroshima and Nagasaki Bombing In addition, the refusal of Japanese troops to surrender and Japan’s “all-out war” have also been put forward as arguments in favor of the bombing that stopped the atrocities of the “all-out war” of Japanese […]
• Did the USA need to drop the bombs on Hiroshima and Nagasaki? However, the war continued along the Pacific Ocean due to the resistance of the Japanese Emperor to sign the instrument of surrender.
• Hiroshima Bombing in Berger’s, Hardy’s, Hersey’s Works Berger used excerpts of the actual witnesses of the bombing to illustrate the scope of the tragedy and made generalizations concerning the horrors of Hiroshima in the historical and global context.
• Hiroshima and Nagasaki: The Long-Term Health Effects Nevertheless, exposure to neutrons from the incidence of A-bomb in Japan, Hiroshima and Nagasaki, is currently thought to have been the sources of just 1-2% of the entire dose of ionizing radiation.
• Hiroshima and Its Importance in US History Hiroshima is the capital city of Hiroshima district, which is situated in the south west of the province Honshu in Japan.
• The Atomic Bomb of Hiroshima The effects of the bombing were devastating; the explosion had a blast equivalent to approximately 13 kilotons of TNT. Sasaki says that hospitals were teaming with the wounded people, those who managed to survive the […]
• Bombing of Hiroshima and Nagasaki: Historic Attitudes Surely, the atomic bombing of the two cities could not have been the only way to get the Japanese to surrender.
• Hiroshima, Nagasaki and the Theory of Just War The theory of Just War is meant to provide a philosophical framework, upon which the use of military force is justified. Was the use of the bomb a last resort?
• Hiroshima Bombing Occurrence and Impacts Additionally, all the other disasters follow a path that is off firebombing as compared to the Hiroshima that saw the only use of nuclear weapons. However, research that is more empirical should to establish the […]
• Memory by Analogy: Hiroshima Mon Amour It is quite painful to recall the events that took place in Japan during the Second World War in the aftermath of the atomic bombing of the cities of Nagasaki and Hiroshima.
• The Atomic Weapons Attacks On Hiroshima And Nagasaki
• Lifton and Mitchell’s Hiroshima in America
• The War Of Hiroshima And Nagasaki Ended The World War II
• Hiroshima And The Inheritance Of Trauma
• Was Bombing Hiroshima And Nagasaki Necessary To End World War 2
• US Bombing of Hiroshima and Nagasaki Cannot be Justified
• Truman ‘s Announcement On Bombing Of Hiroshima
• Speculations about the Cause and Effect of the Atomic Bomb and Its Consequences on Hiroshima and Nagasaki
• US Government Justifies Dropping of Atomic Bomb in Hiroshima
• Things Fall Apart By Chinua Achebe And Hiroshima
• Was the U.S. Right or Wrong Using the Atomic Bomb in Hiroshima
• Swallowing the Poison Mushroom – America After Hiroshima
• The Atomic Explosion Of Hiroshima And Nagasaki
• The Events Before and After the Explosion in John Hersey’s Hiroshima
• The Alternatives to Dropping the Atomic Bombs on Hiroshima and Nagasaki
• To What Extent Were The Bombings Of Hiroshima And Nagasaki
• The Dropping of the Atomic Bomb the Japanese City of Hiroshima
• John Hersey’s Interviews of Hiroshima Atomic Bomb Victims
• Weapons Of Mass Destruction Of Hiroshima And Nagasaki
• The Bombing Of Hiroshima And Nagasaki During World War II
• The Devastation in the City of Hiroshima After the Atomic Bombing in 1945
• Hiroshima And The American Naval Base At Pearl Harbor
• Horrors Caused by the Dropping of the Atomic Bomb on Hiroshima and Nagasaki
• The Aftermath When the Bomb Went off in the Book Hiroshima by John Hershey
• Why President Truman Decided To Drop Atomic Bombs On Hiroshima And Nagasaki
• Saving Lives by Dropping Atomic Bombs on Hiroshima and Nagasaki
• The Background Information of the Hiroshima Bombing and Its Place in U.S. History
• The Events in 1945 During the Atomic Bombing of Hiroshima in Japan by the U.S
• Was the Dropping of the Atomic Bomb on Hiroshima and Nagasaki Justified
• The Background of the Atomic Bomb Little Boy Dropped on Hiroshima in 1945
• The Consequences of the Atomic Bombing of Hiroshima and Nagasaki by the United States
• The Unnecessary Nuclear Attacks On Nagasaki And Hiroshima
• The Controversy and Justification Around the Use of Nuclear Weapons in Hiroshima and Nagasaki
• Imperil Global Disarmament Efforts After Nagasaki and Hiroshima Bombings
• The Ethical Analysis of the Bombings of Hiroshima and Nagasaki
• Literary Documentation of the Cold War in John Hersey’s Hiroshima
• The Attack On Hiroshima And Nagasaki
• Was America Justified in Dropping the Atomic Bomb on Hiroshima in August 1945
• Hiroshima and Nagasaki Bombings as the Events that Ended World War II
• The Bombing of Hiroshima Changed Six Individuals
• The Debate Over the Ethics of the Atomic Bombing of Hiroshima and Nagasaki
• Why Did The Americans Drop The Atomic Bomb On Hiroshima
• Was the US Justified in Dropping Atomic Bombs on Hiroshima and Nagasaki
• The US Decision to Drop the Atomic Bomb in Hiroshima
• Hiroshima Nagasaki: Entering Into The Atomic Age
• Why the United States Should Have Dropped the Atomic Bomb on Hiroshima
• Why America Bombed Hiroshima and Nagasaki
• Was The Atomic Bombing Of Hiroshima And Hiroshima Justified
• Hiroshima Almost Wiped off From the Face of the Earth
• The Bombing of Hiroshima and the Attack on Pearl Harbor During the WWII
• Were Bombing Hiroshima and Nagasaki Necessary to End World War 2?
• Was the Atomic Bomb Dropped on Hiroshima Justified?
• Was the U.S. Right or Wrong Using the Atomic Bomb in Hiroshima?
• Why Did the US Pick Hiroshima To Bomb?
• What Did the Hiroshima Bomb Do to Humans?
• How Many Were Killed in Hiroshima?
• Were the Hiroshima and Nagasaki Bombings the Acts of Genocide?
• How Do the Japanese Feel About Hiroshima Many Years Later?
• How Many Years Does It Take for Hiroshima To Fully Recover?
• How Long After Hiroshima Did Japan Surrender?
• Why Was the Bombing of Hiroshima Immoral?
• Was Hiroshima a Human Rights Violation?
• Was Hiroshima Bombing a Secret Message to Soviets?
• What Were the International Politics Before and After Hiroshima?
• What Is the Hiroshima Exhibit Controversy?
• What Is the Incidence of Leukemia in Survivors of the Atomic Bomb in Hiroshima?
• Does Tourism Illuminate the Darkness of Hiroshima and Nagasaki?
• What Is the Effect of Bombing on Pregnancy Termination in Hiroshima?
• Why Did the US Drop the Second Atomic Bomb After Hiroshima?
• Is There Still Radioactivity in Hiroshima?
• How Long Until Hiroshima Was Habitable and Why It Takes Time?
• How Did Hiroshima Recover So Quickly?
• Did the US Help Japan After the Hiroshima and Nagasaki?
• How Hiroshima Atomic Bomb Survivors Have Transformed Our Mindset?
• What Were the Genetic Effects of Radiation in Hiroshima Survivors?
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Introduction

The purpose of this guide is to assist with researching j. r. oppenheimer, and the atomic bomb that ended wwii..

"Now, I am become Death, the destroyer of worlds" -Bhagavad Gita.   Hindi quote recited by J. Robert Oppenheimer after the plutonium implosion test in Los Alamos, New Mexico on July 16, 1945.

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• Nuclear Dawn by James P. Delgado Call Number: UG1282.A8 D45 2009 ISBN: 1846033969 Publication Date: 2009-09-22 The obliteration of Hiroshima and Nagasaki in August 1945 brought the world to a stand still. This unimaginable shock confirmed to the world that the race to develop a working atomic weapon during World War II had been won by the American-led international effort. Horrific and controversial even today, these first uses of the atomic bomb had intense ramifications not only on the continued development of the bomb, but also on politics and popular culture.

• The Road to Trinity by K. D. Nichols Call Number: QC774.N45 A3 1987 ISBN: 9780688069100 Publication Date: 1987-07-01 This account details the author's involvement in the development of the first atomic bomb, his contributions to international control of atomic weapons and his role in the early development of atomic military doctrine during the Cold War. Nichols was wartime district engineer for the Manhattan Project, general manager of the Atomic Energy Commission and, for three decades, a consultant in the atomic power industry.

• Atomic Bomb This video clip contains footage of the aftermath of the first atomic bomb dropped on Japan (8/7/45, Hiroshima) and an A-bomb test in the United States (5/15/52, Yucca Flat, Nevada).
• Atomic Bomb Newsreel ca. 1945 t the start of World War II the United States conducted secret research on nuclear fission in the quest to develop the atomic bomb. On July 16, 1945, the first atomic bomb was successfully tested in New Mexico. On August 6, 1945, President Harry S. Truman authorized the drop of two atomic bombs on the Japanese cities of Hiroshima and Nagasaki, swiftly ending World War II. No atomic weapon has been detonated in wartime since.
• Pictures from a Hiroshima Schoolyard PICTURES FROM A HIROSHIMA SCHOOLYARD presents the aftermath of the first atomic bomb through the remarkable drawings and stories of surviving Japanese school children who were part of an extraordinary, compassionate exchange with their American counterparts after the war.
• Countdown to Zero COUNTDOWN TO ZERO traces the history of the atomic bomb from its origins to the present state of global affairs. The film makes a compelling case for worldwide nuclear disarmament, an issue more topical than ever.
• Turning Points in Modern History EPISODE 20 1942—The Dawn of the Atom When German physicists split the atom, Albert Einstein warned President Roosevelt of the potential for “extremely powerful bombs of a new type.” Chart the course of the nuclear bomb from this letter through the first nuclear chain reaction led by physicist Enrico Fermi, the Manhattan Project, and devastation in Hiroshima and Nagasaki.
• Manhattan Project The scientists and engineers who helped build the world's first nuclear weapon reflect on their accomplishments and legacy. The explosion took place, appropriately, in an area of the New Mexico desert called jornada del muerto—the journey of death. At 5:30 AM on July 16, 1945, the first atomic bomb was detonated and a new era began.
• World War II: The Pacific Theater: From Pearl Harbor to Nagasaki Learn all about The Pacific Theater of World War II and the pivotal battles along the way. Why did Japan attack Pearl Harbor? Who were the Allied Powers? What happened at the Battle of Iwo Jima? What was the Manhattan Project? Why did the United States drop the atomic bomb at Hiroshima and Nagasaki? The answers to these questions and more are covered in depth with detailed graphics, diagrams and dynamic video that reinforce important concepts.
• "Hiroshima" In 1942, the United States government embarked upon an endeavor it hoped would put a quick and definite end to World War II. Under extraordinary secrecy and with unlimited funds, the top scientists of the day were brought together to work on the Manhattan Project - and on August 6, 1945, three years of technological advancements were exploded above Hiroshima in the form of a uranium-fission bomb. This episode of Tech Effect profiles the technology surrounding that fateful moment. The advanced B-29 bomber, the sophisticated Norden bombsight, Mamiya and K-20 aerial cameras, telemetry canisters, and even Teflon have a place in this grim yet remarkable story.
• The Bomb The Bomb tells the story of the most powerful and destructive device ever invented. Learn how humans harnessed this incredible power and what challenges we have faced living with it since 1945. With newly restored footage of nuclear weaponry, some of which has only recently been declassified, go behind the scenes of the first atomic bomb, revealing how it was developed and how it changed the planet, ushering in a new era and reshaping our lives even today.
• Hiroshima No Pika Hiroshima No Pika is an animated film made by Noriaki Tsuchimoto based on the award-winning children’s book by the Japanese artist Toshi Maruki. Through Maruki's heart-rending but beautiful water color illustrations, the film tells the story of a young girl and her family who live through the horrific bombing of Hiroshima.
• The trials of J. Robert Oppenheimer J. Robert Oppenheimer's life and legacy are inextricably linked to America's most famous top-secret initiative - the Manhattan Project. This biography presents a complex and revealing portrait of one of America's most influential scientists.
• Atomic Heritage Foundation The Atomic Heritage Foundation (AHF), founded by Cynthia Kelly in 2002, is a 501(c)3 nonprofit organization in Washington, DC, dedicated to the preservation and interpretation of the Manhattan Project and the Atomic Age and its legacy.
• Department of Energy OpenNet System The OpenNet database provides easy, timely access to approximately 512,000 bibliographic references and over 130,000 with attached full-text, including information declassified in response to Freedom of Information Act requests. In addition to these documents, OpenNet references older document collections from several DOE sources.
• National Achieves Catalog Advisory Committee on Human Radiation Experiments-Markey Report/CIA Report. This report describes material contained in Department of Energy documents on radiation experiments using human subjects.
• National Museum of Nuclear Science & History The National Museum of Nuclear Science & History was established in 1969 as an intriguing place to learn the story of the Atomic Age, from early research of nuclear development through today’s peaceful uses of nuclear technology.
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• U. S. Department of Energy Opennet The mission of the Energy Department is to ensure America’s security and prosperity by addressing its energy, environmental and nuclear challenges through transformative science and technology solutions. Learn more.
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• A Slow Painful Death The man-made element, plutonium, number 94 in the periodic table, is dangerous because it not only kills outright with burns and radiation sickness, but it causes cancer, sometimes decades after a person is exposed. Once plutonium is introduced into the body it cannot be gotten rid of: It takes 24,065 years for half the plutonium to decay.
• African Americans & the Manhattan Project Thousands of African American women and men contributed to the Manhattan Project, but many of their stories remain untold. They were an important part of the workforce, especially at Hanford and Oak Ridge. More than 15,000 African Americans arrived in the Tri-Cities during the Manhattan Project. Approximately 7,000 African Americans worked in Oak Ridge for the Manhattan Project.
• Atomic Bomb and the Dawning of the Nuclear Age The atomic bomb was developed toward the end of World War II (1939–1945), ushering in the start of the "nuclear age." Such weapons could devastate large areas with relative ease. Furthermore, their effects lingered long after the initial blast, destroying natural environments and making people ill.
• Hispanic Homesteaders and the Los Alamos National Laboratory The Homestead Act of 1862 provided 160 acres of land to United States citizens who lived on, farmed, and improved the land for at least five years. Los Alamos County like much of the western United States was home to many homesteaders. Although people had been using the Pajarito Plataeu on a seasonal basis, homesteading originally began in March 1887 when Juan Louis Garcia filed for a homesteaded. The majority of the homesteaders on the plataeu were Hispanic.
• Inside Story Of Kilgore's Rise: Farm Hand To Industrialist B & T Metals: The African American-Owned Company that Helped Win the Race for the Atomic Bomb After he died in the summer of 1948, The Ohio State News recognized Mr. Kilgore’s tenacity in building a major industry, a feat “that many industrialists considered impossible.” What the newspaper did not know at the time was that Kilgore’s company had also helped the United States win its top-secret race for the atomic bomb.
• J. Robert Oppenheimer’s Interview Hear in his own words Oppenheimer talk about the Manhattan Project and the scientist he helped recruit.
• J. Robert Oppenheimer Personnel Hearings Transcripts In December 1953, the Atomic Energy Commission (AEC) suspended the security clearance of Dr. J. Robert Oppenheimer, and after a four-week, closed-door hearing in April and May 1954, formally revoked that clearance. In June 1954, the AEC released a redacted version of the hearing transcript, (see AEC press release), with security classified information deleted, published by the Government Printing Office (GPO) under the title, In the Matter of J. Robert Oppenheimer: Transcript of Hearing before Personnel Security Board.
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• Manhattan Project Resources The Manhattan Project: Resources is a joint collaboration between the Department of Energy’s Office of Classification and Office of History and Heritage Resources. This effort is designed to disseminate information and documentation on the Manhattan Project to a broad audience including scholars, students, and the general public.
• Nature Immersion in an Extreme Environment: Hiroshima Survivors' Personal Emergence Following Their Atomic Bomb Experience Synchrony, as a dimension of human connection with nature, transcended the disharmony of bombing upheaval. Although further exploration is necessary, these findings serve as evidence about the essence of healing as related to nature for those in extreme environments.
• Nevada National Security Site Environmental Report Summary 2016 DOE/NV/25946--3334-SUM Environmental Report Summary 2016 September 2017 National Nuclear Security Administration National Security Technologies LL
• ‘Now I am become death, destroyer of worlds’: science, perversion, psychoanalysis This article offers a critical examination of the contemporary imperative to ‘trust science’ from the point of view of Lacanian psychoanalysis. It begins by putting contemporary scientific research in the twentieth-century historical context of the ‘military-industrial complex’ (D. Eisenhower) in which science and technology become symbiotically connected to the military.
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• Series: The Life of J. Robert Oppenheimer A controversial figure to this day, J. Robert Oppenheimer led the development and construction of the world's first atomic weapons. This article series explores his life from a young man, to his role in the Manhattan Project, to his blacklisting at the height of the Cold War's "Red Scare."
• TU-D-204-01: Making of the Atomic Bomb This lecture will present the extraordinary historical genesis and the thoughts of great men and women in the development of the atomic bomb. In addition, the difficult military and political decisions will be covered such as: target selection, the debate over whether to give the Japanese government a demonstration of its power and whether to use it at all. Also, were the German and Japanese scientists developing there own bomb? Declassified top secret documents now help in answering some of these questions.
• The Human Guinea Pigs at Bikini Focuses on the contents of papers and letters discovered in the library of the University of California, regarding atomic bomb tests in 1946 on Bikini Atoll, Marshall Islands.
• Operation REDWING, Operation Order No. 1-56 Task Group 7.1 The Operation Plan covers and outlines the pertinent missions and tasks of Task Group 7.1. It also is intended as a guide to assist personnel in planning and carrying out their individual tasks since it represents a record of agreements arrived at prior to its compilation.

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The Atomic Bomb and the End of World War II

A Collection of Primary Sources

Updated National Security Archive Posting Marks 75th Anniversary of the Atomic Bombings of Japan and the End of World War II

Extensive Compilation of Primary Source Documents Explores Manhattan Project, Eisenhower’s Early Misgivings about First Nuclear Use, Curtis LeMay and the Firebombing of Tokyo, Debates over Japanese Surrender Terms, Atomic Targeting Decisions, and Lagging Awareness of Radiation Effects

Washington, D.C., August 4, 2020 –  To mark the 75th anniversary of the atomic bombings of Hiroshima and Nagasaki in August 1945, the National Security Archive is updating and reposting one of its most popular e-books of the past 25 years. 

While U.S. leaders hailed the bombings at the time and for many years afterwards for bringing the Pacific war to an end and saving untold thousands of American lives, that interpretation has since been seriously challenged.  Moreover, ethical questions have shrouded the bombings which caused terrible human losses and in succeeding decades fed a nuclear arms race with the Soviet Union and now Russia and others.

Three-quarters of a century on, Hiroshima and Nagasaki remain emblematic of the dangers and human costs of warfare, specifically the use of nuclear weapons.  Since these issues will be subjects of hot debate for many more years, the Archive has once again refreshed its compilation of declassified U.S. government documents and translated Japanese records that first appeared on these pages in 2005.

*    *    *    *    *

Introduction

By William Burr

The 75th anniversary of the atomic bombings of Hiroshima and Nagasaki in August 1945 is an occasion for sober reflection. In Japan and elsewhere around the world, each anniversary is observed with great solemnity. The bombings were the first time that nuclear weapons had been detonated in combat operations.  They caused terrible human losses and destruction at the time and more deaths and sickness in the years ahead from the radiation effects. And the U.S. bombings hastened the Soviet Union’s atomic bomb project and have fed a big-power nuclear arms race to this day. Thankfully, nuclear weapons have not been exploded in war since 1945, perhaps owing to the taboo against their use shaped by the dropping of the bombs on Japan. 

Along with the ethical issues involved in the use of atomic and other mass casualty weapons, why the bombs were dropped in the first place has been the subject of sometimes heated debate. As with all events in human history, interpretations vary and readings of primary sources can lead to different conclusions.  Thus, the extent to which the bombings contributed to the end of World War II or the beginning of the Cold War remain live issues.  A significant contested question is whether, under the weight of a U.S. blockade and massive conventional bombing, the Japanese were ready to surrender before the bombs were dropped.  Also still debated is the impact of the Soviet declaration of war and invasion of Manchuria, compared to the atomic bombings, on the Japanese decision to surrender. Counterfactual issues are also disputed, for example whether there were alternatives to the atomic bombings, or would the Japanese have surrendered had a demonstration of the bomb been used to produced shock and awe. Moreover, the role of an invasion of Japan in U.S. planning remains a matter of debate, with some arguing that the bombings spared many thousands of American lives that otherwise would have been lost in an invasion.

Those and other questions will be subjects of discussion well into the indefinite future. Interested readers will continue to absorb the fascinating historical literature on the subject.  Some will want to read declassified primary sources so they can further develop their own thinking about the issues. Toward that end, in 2005, at the time of the 60th anniversary of the bombings, staff at the National Security Archive compiled and scanned a significant number of declassified U.S. government documents to make them more widely available. The documents cover multiple aspects of the bombings and their context.  Also included, to give a wider perspective, were translations of Japanese documents not widely available before.  Since 2005, the collection has been updated. This latest iteration of the collection includes corrections, a few minor revisions, and updated footnotes to take into account recently published secondary literature.

2015 Update

August 4, 2015 – A few months after the atomic bombings of Hiroshima and Nagasaki, General Dwight D.  Eisenhower commented during a social occasion “how he had hoped that the war might have ended without our having to use the atomic bomb.” This virtually unknown evidence from the diary of Robert P. Meiklejohn, an assistant to Ambassador W. Averell Harriman, published for the first time today by the National Security Archive, confirms that the future President Eisenhower had early misgivings about the first use of atomic weapons by the United States. General George C. Marshall is the only high-level official whose contemporaneous (pre-Hiroshima) doubts about using the weapons against cities are on record.

On the 70th anniversary of the bombing of Hiroshima on August 6, 1945, the National Security Archive updates its 2005 publication of the most comprehensive on-line collection of declassified U.S. government documents on the first use of the atomic bomb and the end of the war in the Pacific. This update presents previously unpublished material and translations of difficult-to-find records. Included are documents on the early stages of the U.S. atomic bomb project, Army Air Force General  Curtis LeMay’s report  on the firebombing of Tokyo (March 1945), Secretary of War Henry  Stimson’s requests  for modification of unconditional surrender terms,  Soviet documents  relating to the events, excerpts from the Robert P. Meiklejohn diaries mentioned above, and selections from the diaries of Walter J. Brown, special assistant to Secretary of State James Byrnes.

The original 2005 posting included a wide range of material, including formerly top secret "Magic" summaries of intercepted Japanese communications and the first-ever full translations from the Japanese of accounts of high level meetings and discussions in Tokyo leading to the Emperor’s decision to surrender. Also documented are U.S. decisions to target Japanese cities, pre-Hiroshima petitions by scientists questioning the military use of the A-bomb, proposals for demonstrating the effects of the bomb, debates over whether to modify unconditional surrender terms, reports from the bombing missions of Hiroshima and Nagasaki, and belated top-level awareness of the radiation effects of atomic weapons.

The documents can help readers to make up their own minds about long-standing controversies such as whether the first use of atomic weapons was justified, whether President Harry S. Truman had alternatives to atomic attacks for ending the war, and what the impact of the Soviet declaration of war on Japan was. Since the 1960s, when the declassification of important sources began, historians have engaged in vigorous debate over the bomb and the end of World War II. Drawing on sources at the National Archives and the Library of Congress as well as Japanese materials, this electronic briefing book includes key documents that historians of the events have relied upon to present their findings and advance their interpretations.

The Atomic Bomb and the End of World War II: A Collection of Primary Sources

Seventy years ago this month, the United States dropped atomic bombs on Hiroshima and Nagasaki, the Soviet Union declared war on Japan, and the Japanese government surrendered to the United States and its allies. The nuclear age had truly begun with the first military use of atomic weapons. With the material that follows, the National Security Archive publishes the most comprehensive on-line collection to date of declassified U.S. government documents on the atomic bomb and the end of the war in the Pacific. Besides material from the files of the Manhattan Project, this collection includes formerly “Top Secret Ultra” summaries and translations of Japanese diplomatic cable traffic intercepted under the “Magic” program. Moreover, the collection includes for the first time translations from Japanese sources of high level meetings and discussions in Tokyo, including the conferences when Emperor Hirohito authorized the final decision to surrender. [1]

Ever since the atomic bombs were exploded over Japanese cities, historians, social scientists, journalists, World War II veterans, and ordinary citizens have engaged in intense controversy about the events of August 1945. John Hersey’s  Hiroshima , first published in the New Yorker  in 1946 encouraged unsettled readers to question the bombings while church groups and some commentators, most prominently Norman Cousins, explicitly criticized them. Former Secretary of War Henry Stimson found the criticisms troubling and published an influential justification for the attacks in  Harper’s . [2] During the 1960s the availability of primary sources made historical research and writing possible and the debate became more vigorous. Historians Herbert Feis and Gar Alperovitz raised searching questions about the first use of nuclear weapons and their broader political and diplomatic implications. The controversy, especially the arguments made by Alperovitz and others about “atomic diplomacy” quickly became caught up in heated debates over Cold War “revisionism.” The controversy simmered over the years with major contributions by Martin Sherwin and Barton J. Bernstein but it became explosive during the mid-1990s when curators at the National Air and Space Museum met the wrath of the Air Force Association over a proposed historical exhibit on the Enola Gay. [3] The NASM exhibit was drastically scaled-down but historians and journalist continued to engage in the debate. Alperovitz, Bernstein, and Sherwin made new contributions as did other historians, social scientists, and journalists including Richard B. Frank, Herbert Bix, Sadao Asada, Kai Bird, Robert James Maddox, Sean Malloy, Robert P. Newman, Robert S. Norris, Tsuyoshi Hagesawa, and J. Samuel Walker. [4]

The continued controversy has revolved around the following, among other, questions:

• were the atomic strikes necessary primarily to avert an invasion of Japan in November 1945?
• Did Truman authorize the use of atomic bombs for diplomatic-political reasons-- to intimidate the Soviets--or was his major goal to force Japan to surrender and bring the war to an early end?
• If ending the war quickly was the most important motivation of Truman and his advisers to what extent did they see an “atomic diplomacy” capability as a “bonus”?
• To what extent did subsequent justification for the atomic bomb exaggerate or misuse wartime estimates for U.S. casualties stemming from an invasion of Japan?
• Were there alternatives to the use of the weapons? If there were, what were they and how plausible are they in retrospect? Why were alternatives not pursued?
• How did the U.S. government plan to use the bombs? What concepts did war planners use to select targets? To what extent were senior officials interested in looking at alternatives to urban targets? How familiar was President Truman with the concepts that led target planners chose major cities as targets?
• What did senior officials know about the effects of atomic bombs before they were first used. How much did top officials know about the radiation effects of the weapons?
• Did President Truman make a decision, in a robust sense, to use the bomb or did he inherit a decision that had already been made?
• Were the Japanese ready to surrender before the bombs were dropped? To what extent had Emperor Hirohito prolonged the war unnecessarily by not seizing opportunities for surrender?
• If the United States had been more flexible about the demand for “unconditional surrender” by explicitly or implicitly guaranteeing a constitutional monarchy would Japan have surrendered earlier than it did?
• How decisive was the atomic bombings to the Japanese decision to surrender?
• Was the bombing of Nagasaki unnecessary? To the extent that the atomic bombing was critically important to the Japanese decision to surrender would it have been enough to destroy one city?
• Would the Soviet declaration of war have been enough to compel Tokyo to admit defeat?
• Was the dropping of the atomic bombs morally justifiable?

This compilation will not attempt to answer these questions or use primary sources to stake out positions on any of them. Nor is it an attempt to substitute for the extraordinary rich literature on the atomic bombings and the end of World War II. Nor does it include any of the interviews, documents prepared after the events, and post-World War II correspondence, etc. that participants in the debate have brought to bear in framing their arguments. Originally this collection did not include documents on the origins and development of the Manhattan Project, although this updated posting includes some significant records for context. By providing access to a broad range of U.S. and Japanese documents, mainly from the spring and summer of 1945, interested readers can see for themselves the crucial source material that scholars have used to shape narrative accounts of the historical developments and to frame their arguments about the questions that have provoked controversy over the years. To help readers who are less familiar with the debates, commentary on some of the documents will point out, although far from comprehensively, some of the ways in which they have been interpreted. With direct access to the documents, readers may develop their own answers to the questions raised above. The documents may even provoke new questions.

Contributors to the historical controversy have deployed the documents selected here to support their arguments about the first use of nuclear weapons and the end of World War II. The editor has closely reviewed the footnotes and endnotes in a variety of articles and books and selected documents cited by participants on the various sides of the controversy. [5] While the editor has a point of view on the issues, to the greatest extent possible he has tried to not let that influence document selection, e.g., by selectively withholding or including documents that may buttress one point of view or the other. The task of compilation involved consultation of primary sources at the National Archives, mainly in Manhattan Project files held in the records of the Army Corps of Engineers, Record Group 77, but also in the archival records of the National Security Agency. Private collections were also important, such as the Henry L. Stimson Papers held at Yale University (although available on microfilm, for example, at the Library of Congress) and the papers of W. Averell Harriman at the Library of Congress. To a great extent the documents selected for this compilation have been declassified for years, even decades; the most recent declassifications were in the 1990s.

The U.S. documents cited here will be familiar to many knowledgeable readers on the Hiroshima-Nagasaki controversy and the history of the Manhattan Project. To provide a fuller picture of the transition from U.S.-Japanese antagonism to reconciliation, the editor has done what could be done within time and resource constraints to present information on the activities and points of view of Japanese policymakers and diplomats. This includes a number of formerly top secret summaries of intercepted Japanese diplomatic communications, which enable interested readers to form their own judgments about the direction of Japanese diplomacy in the weeks before the atomic bombings. Moreover, to shed light on the considerations that induced Japan’s surrender, this briefing book includes new translations of Japanese primary sources on crucial events, including accounts of the conferences on August 9 and 14, where Emperor Hirohito made decisions to accept Allied terms of surrender.

[ Editor’s Note: Originally prepared in July 2005 this posting has been updated, with new documents, changes in organization, and other editorial changes. As noted, some documents relating to the origins of the Manhattan Project have been included in addition to entries from the Robert P. Meiklejohn diaries and translations of a few Soviet documents, among other items. Moreover, recent significant contributions to the scholarly literature have been taken into account.]

I. Background on the U.S. Atomic Project

Documents 1A-C: Report of the Uranium Committee

1A . Arthur H. Compton, National Academy of Sciences Committee on Atomic Fission, to Frank Jewett, President, National Academy of Sciences, 17 May 1941, Secret

1B . Report to the President of the National Academy of Sciences by the Academy Committee on Uranium, 6 November 1941, Secret

1C . Vannevar Bush, Director, Office of Scientific Research and Development, to President Roosevelt, 27 November 1941, Secret

Source: National Archives, Records of the Office of Scientific Research and Development, Record Group 227 (hereinafter RG 227), Bush-Conant papers microfilm collection, Roll 1, Target 2, Folder 1, "S-1 Historical File, Section A (1940-1941)."

This set of documents concerns the work of the Uranium Committee of the National Academy of Sciences, an exploratory project that was the lead-up to the actual production effort undertaken by the Manhattan Project. The initial report, May 1941, showed how leading American scientists grappled with the potential of nuclear energy for military purposes. At the outset, three possibilities were envisioned: radiological warfare, a power source for submarines and ships, and explosives. To produce material for any of those purposes required a capability to separate uranium isotopes in order to produce fissionable U-235. Also necessary for those capabilities was the production of a nuclear chain reaction. At the time of the first report, various methods for producing a chain reaction were envisioned and money was being budgeted to try them out.

Later that year, the Uranium Committee completed its report and OSRD Chairman Vannevar Bush reported the findings to President Roosevelt: As Bush emphasized, the U.S. findings were more conservative than those in the British MAUD report: the bomb would be somewhat “less effective,” would take longer to produce, and at a higher cost. One of the report’s key findings was that a fission bomb of superlatively destructive power will result from bringing quickly together a sufficient mass of element U235.” That was a certainty, “as sure as any untried prediction based upon theory and experiment can be.” The critically important task was to develop ways and means to separate highly enriched uranium from uranium-238. To get production going, Bush wanted to establish a “carefully chosen engineering group to study plans for possible production.” This was the basis of the Top Policy Group, or the S-1 Committee, which Bush and James B. Conant quickly established. [6]

In its discussion of the effects of an atomic weapon, the committee considered both blast and radiological damage. With respect to the latter, “It is possible that the destructive effects on life caused by the intense radioactivity of the products of the explosion may be as important as those of the explosion itself.” This insight was overlooked when top officials of the Manhattan Project considered the targeting of Japan during 1945. [7]

Documents 2A-B: Going Ahead with the Bomb

2A : Vannevar Bush to President Roosevelt, 9 March 1942, with memo from Roosevelt attached, 11 March 1942, Secret

2B : Vannevar Bush to President Roosevelt, 16 December 1942, Secret (report not attached)

Sources: 2A: RG 227, Bush-Conant papers microfilm collection, Roll 1, Target 2, Folder 1, "S-1 Historical File, Section II (1941-1942): 2B: Bush-Conant papers, S-1 Historical File, Reports to and Conferences with the President (1942-1944)

The Manhattan Project never had an official charter establishing it and defining its mission, but these two documents are the functional equivalent of a charter, in terms of presidential approvals for the mission, not to mention for a huge budget. In a progress report, Bush told President Roosevelt that the bomb project was on a pilot plant basis, but not yet at the production stage. By the summer, once “production plants” would be at work, he proposed that the War Department take over the project. In reply, Roosevelt wrote a short memo endorsing Bush’s ideas as long as absolute secrecy could be maintained. According to Robert S. Norris, this was “the fateful decision” to turn over the atomic project to military control. [8]

Some months later, with the Manhattan Project already underway and under the direction of General Leslie Grove, Bush outlined to Roosevelt the effort necessary to produce six fission bombs. With the goal of having enough fissile material by the first half of 1945 to produce the bombs, Bush was worried that the Germans might get there first. Thus, he wanted Roosevelt’s instructions as to whether the project should be “vigorously pushed throughout.” Unlike the pilot plant proposal described above, Bush described a real production order for the bomb, at an estimated cost of a “serious figure”: $400 million, which was an optimistic projection given the eventual cost of $1.9 billion. To keep the secret, Bush wanted to avoid a “ruinous” appropriations request to Congress and asked Roosevelt to ask Congress for the necessary discretionary funds. Initialed by President Roosevelt (“VB OK FDR”), this may have been the closest that he came to a formal approval of the Manhattan Project.

Document 3 : Memorandum by Leslie R. Grove, “Policy Meeting, 5/5/43,” Top Secret

Source:  National Archives, Record Group 77, Records of the Army Corps of Engineers (hereinafter RG 77), Manhattan Engineering District (MED), Minutes of the Military Policy Meeting (5 May 1943), Correspondence (“Top Secret”) of the Manhattan Engineer District, 1942-1946, microfilm publication M1109 (Washington, D.C.: National Archives and Records Administration, 1980), Roll 3, Target 6, Folder 23, “Military Policy Committee, Minutes of Meetings”

Before the Manhattan Project had produced any weapons, senior U.S. government officials had Japanese targets in mind. Besides discussing programmatic matters (e.g., status of gaseous diffusion plants, heavy water production for reactors, and staffing at Las Alamos), the participants agreed that the first use could be Japanese naval forces concentrated at Truk Harbor, an atoll in the Caroline Islands. If there was a misfire the weapon would be difficult for the Japanese to recover, which would not be the case if Tokyo was targeted. Targeting Germany was rejected because the Germans were considered more likely to “secure knowledge” from a defective weapon than the Japanese. That is, the United States could possibly be in danger if the Nazis acquired more knowledge about how to build a bomb. [9]

Document 4 :   Memo from General Groves to the Chief of Staff [Marshall], “Atomic Fission Bombs – Present Status and Expected Progress,” 7 August 1944, Top Secret, excised copy

Source: RG 77, Correspondence ("Top Secret") of the Manhattan Engineer District, 1942-1946, file 25M

This memorandum from General Groves to General Marshall captured how far the Manhattan Project had come in less than two years since Bush’s December 1942 report to President Roosevelt .  Groves did not mention this but around the time he wrote this the Manhattan Project had working at its far-flung installations over  125,000 people  ; taking into account high labor turnover some 485,000 people worked on the project (1 out of every 250 people in the country at that time). What these people were laboring to construct, directly or indirectly, were two types of weapons—a gun-type weapon using U-235 and an implosion weapon using plutonium (although the possibility of U-235 was also under consideration). As the scientists had learned, a gun-type weapon based on plutonium was “impossible” because that element had an “unexpected property”: spontaneous neutron emissions would cause the weapon to “fizzle.” [10]  For both the gun-type and the implosion weapons, a production schedule had been established and both would be available during 1945. The discussion of weapons effects centered on blast damage models; radiation and other effects were overlooked.

Document 5 : Memorandum from Vannevar Bush and James B. Conant, Office of Scientific Research and Development, to Secretary of War, September 30, 1944, Top Secret

Source: RG 77, Harrison-Bundy Files (H-B Files), folder 69 (copy from microfilm)

While Groves worried about the engineering and production problems, key War Department advisers were becoming troubled over the diplomatic and political implications of these enormously powerful weapons and the dangers of a global nuclear arms race. Concerned that President Roosevelt had an overly “cavalier” belief about the possibility of maintaining a post-war Anglo-American atomic monopoly, Bush and Conant recognized the limits of secrecy and wanted to disabuse senior officials of the notion that an atomic monopoly was possible. To suggest alternatives, they drafted this memorandum about the importance of the international exchange of information and international inspection to stem dangerous nuclear competition. [11]

Documents 6A-D: President Truman Learns the Secret:

6A : Memorandum for the Secretary of War from General L. R. Groves, “Atomic Fission Bombs,” April 23, 1945

6B : Memorandum discussed with the President, April 25, 1945

6C : [Untitled memorandum by General L.R. Groves, April 25, 1945

6D : Diary Entry, April 25, 1945

Sources: A: RG 77, Commanding General’s file no. 24, tab D; B: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress); C: Source: Record Group 200, Papers of General Leslie R. Groves, Correspondence 1941-1970, box 3, “F”; D: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress)

Soon after he was sworn in as president following President Roosevelt’s death, Harry Truman learned about the top secret Manhattan Project from a briefing from Secretary of War Stimson and Manhattan Project chief General Groves, who went through the “back door” to escape the watchful press. Stimson, who later wrote up the meeting in his diary, also prepared a discussion paper, which raised broader policy issues associated with the imminent possession of “the most terrible weapon ever known in human history.” In a background report prepared for the meeting, Groves provided a detailed overview of the bomb project from the raw materials to processing nuclear fuel to assembling the weapons to plans for using them, which were starting to crystallize.

With respect to the point about assembling the weapons, the first gun-type weapon “should be ready about 1 August 1945” while an implosion weapon would also be available that month. “The target is and was always expected to be Japan.” The question whether Truman “inherited assumptions” from the Roosevelt administration that that the bomb would be used has been a controversial one. Alperovitz and Sherwin have argued that Truman made “a real decision” to use the bomb on Japan by choosing “between various forms of diplomacy and warfare.” In contrast, Bernstein found that Truman “never questioned [the] assumption” that the bomb would and should be used. Norris also noted that “Truman’s `decision’ was a decision not to override previous plans to use the bomb.” [12]

II. Targeting Japan

Document 7 : Commander F. L. Ashworth to Major General L.R. Groves, “The Base of Operations of the 509 th  Composite Group,” February 24, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5g

The force of B-29 nuclear delivery vehicles that was being readied for first nuclear use—the Army Air Force’s 509 th  Composite Group—required an operational base in the Western Pacific. In late February 1945, months before atomic bombs were ready for use, the high command selected Tinian, an island in the Northern Marianas Islands, for that base.

Document 8 : Headquarters XXI Bomber Command, “Tactical Mission Report, Mission No. 40 Flown 10 March 1945,”n.d., Secret

Source: Library of Congress, Curtis LeMay Papers, Box B-36

As part of the war with Japan, the Army Air Force waged a campaign to destroy major industrial centers with incendiary bombs. This document is General Curtis LeMay’s report on the firebombing of Tokyo--“the most destructive air raid in history”--which burned down over 16 square miles of the city, killed up to 100,000 civilians (the official figure was 83,793), injured more than 40,000, and made over 1 million homeless.  [13]  According to the “Foreword,” the purpose of the raid, which dropped 1,665 tons of incendiary bombs, was to destroy industrial and strategic targets “ not  to bomb indiscriminately civilian populations.” Air Force planners, however, did not distinguish civilian workers from the industrial and strategic structures that they were trying to destroy.

The killing of workers in the urban-industrial sector was one of the explicit goals of the air campaign against Japanese cities. According to a Joint Chiefs of Staff report on Japanese target systems, expected results from the bombing campaign included: “The absorption of man-hours in repair and relief; the dislocation of labor by casualty; the interruption of public services necessary to production, and above all the destruction of factories engaged in war industry.” While Stimson would later raise questions about the bombing of Japanese cities, he was largely disengaged from the details (as he was with atomic targeting). [14]

Firebombing raids on other cities followed Tokyo, including Osaka, Kobe, Yokahama, and Nagoya, but with fewer casualties (many civilians had fled the cities). For some historians, the urban fire-bombing strategy facilitated atomic targeting by creating a “new moral context,” in which earlier proscriptions against intentional targeting of civilians had eroded. [15]

Document 9 : Notes on Initial Meeting of Target Committee, May 2, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5d (copy from microfilm)

On 27 April, military officers and nuclear scientists met to discuss bombing techniques, criteria for target selection, and overall mission requirements. The discussion of “available targets” included Hiroshima, the “largest untouched target not on the 21 st  Bomber Command priority list.” But other targets were under consideration, including Yawata (northern Kyushu), Yokohama, and Tokyo (even though it was practically “rubble.”) The problem was that the Air Force had a policy of “laying waste” to Japan’s cities which created tension with the objective of reserving some urban targets for nuclear destruction.  [16]

Document 10 : Memorandum from J. R. Oppenheimer to Brigadier General Farrell, May 11, 1945

Source: RG 77, MED Records, Top Secret Documents, File no. 5g (copy from microfilm)

As director of Los Alamos Laboratory, Oppenheimer’s priority was producing a deliverable bomb, but not so much the effects of the weapon on the people at the target. In keeping with General Groves’ emphasis on compartmentalization, the Manhattan Project experts on the effects of radiation on human biology were at the MetLab and other offices and had no interaction with the production and targeting units. In this short memorandum to Groves’ deputy, General Farrell, Oppenheimer explained the need for precautions because of the radiological dangers of a nuclear detonation. The initial radiation from the detonation would be fatal within a radius of about 6/10ths of a mile and “injurious” within a radius of a mile. The point was to keep the bombing mission crew safe; concern about radiation effects had no impact on targeting decisions.  [17]

Document 11 : Memorandum from Major J. A. Derry and Dr. N.F. Ramsey to General L.R. Groves, “Summary of Target Committee Meetings on 10 and 11 May 1945,” May 12, 1945, Top Secret

Scientists and officers held further discussion of bombing mission requirements, including height of detonation, weather, radiation effects (Oppenheimer’s memo), plans for possible mission abort, and the various aspects of target selection, including priority cities (“a large urban area of more than three miles diameter”) and psychological dimension. As for target cities, the committee agreed that the following should be exempt from Army Air Force bombing so they would be available for nuclear targeting: Kyoto, Hiroshima, Yokohama, and Kokura Arsenal. Japan’s cultural capital, Kyoto, would not stay on the list. Pressure from Secretary of War Stimson had already taken Kyoto off the list of targets for incendiary bombings and he would successfully object to the atomic bombing of that city.  [18]

Document 12 : Stimson Diary Entries, May 14 and 15, 1945

Source: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress)

On May 14 and 15, Stimson had several conversations involving S-1 (the atomic bomb); during a talk with Assistant Secretary of War John J. McCloy, he estimated that possession of the bomb gave Washington a tremendous advantage—“held all the cards,” a “royal straight flush”-- in dealing with Moscow on post-war problems: “They can’t get along without our help and industries and we have coming into action a weapon which will be unique.” The next day a discussion of divergences with Moscow over the Far East made Stimson wonder whether the atomic bomb would be ready when Truman met with Stalin in July. If it was, he believed that the bomb would be the “master card” in U.S. diplomacy. This and other entries from the Stimson diary (as well as the entry from the Davies diary that follows) are important to arguments developed by Gar Alperovitz and Barton J. Bernstein, among others, although with significantly different emphases, that in light of controversies with the Soviet Union over Eastern Europe and other areas, top officials in the Truman administration believed that possessing the atomic bomb would provide them with significant leverage for inducing Moscow’s acquiescence in U.S. objectives. [19]

Document 13 : Davies Diary entry for May 21, 1945

Source: Joseph E. Davies Papers, Library of Congress, box 17, 21 May 1945

While officials at the Pentagon continued to look closely at the problem of atomic targets, President Truman, like Stimson, was thinking about the diplomatic implications of the bomb. During a conversation with Joseph E. Davies, a prominent Washington lawyer and former ambassador to the Soviet Union, Truman said that he wanted to delay talks with Stalin and Churchill until July when the first atomic device had been tested. Alperovitz treated this entry as evidence in support of the atomic diplomacy argument, but other historians, ranging from Robert Maddox to Gabriel Kolko, have denied that the timing of the Potsdam conference had anything to do with the goal of using the bomb to intimidate the Soviets. [20]

Document 14 : Letter, O. C. Brewster to President Truman, 24 May 1945, with note from Stimson to Marshall, 30 May 1945, attached, secret

Source: Harrison-Bundy Files relating to the Development of the Atomic Bomb, 1942-1946, microfilm publication M1108 (Washington, D.C.: National Archives and Records Administration, 1980), File 77: "Interim Committee - International Control."

In what Stimson called the “letter of an honest man,” Oswald C. Brewster sent President Truman a profound analysis of the danger and unfeasibility of a U.S. atomic monopoly.  [21]  An engineer for the Kellex Corporation, which was involved in the gas diffusion project to enrich uranium, Brewster recognized that the objective was fissile material for a weapon. That goal, he feared, raised terrifying prospects with implications for the “inevitable destruction of our present day civilization.” Once the U.S. had used the bomb in combat other great powers would not tolerate a monopoly by any nation and the sole possessor would be “be the most hated and feared nation on earth.” Even the U.S.’s closest allies would want the bomb because “how could they know where our friendship might be five, ten, or twenty years hence.” Nuclear proliferation and arms races would be certain unless the U.S. worked toward international supervision and inspection of nuclear plants.

Brewster suggested that Japan could be used as a “target” for a “demonstration” of the bomb, which he did not further define. His implicit preference, however, was for non-use; he wrote that it would be better to take U.S. casualties in “conquering Japan” than “to bring upon the world the tragedy of unrestrained competitive production of this material.”

Document 15 : Minutes of Third Target Committee Meeting – Washington, May 28, 1945, Top Secret

More updates on training missions, target selection, and conditions required for successful detonation over the target. The target would be a city--either Hiroshima, Kyoto (still on the list), or Niigata--but specific “aiming points” would not be specified at that time nor would industrial “pin point” targets because they were likely to be on the “fringes” a city. The bomb would be dropped in the city’s center. “Pumpkins” referred to bright orange, pumpkin-shaped high explosive bombs—shaped like the “Fat Man” implosion weapon--used for bombing run test missions.

Document 16 : General Lauris Norstad to Commanding General, XXI Bomber Command, “509 th  Composite Group; Special Functions,” May 29, 1945, Top Secret

The 509 th  Composite Group’s cover story for its secret mission was the preparation of “Pumpkins” for use in battle. In this memorandum, Norstad reviewed the complex requirements for preparing B-29s and their crew for successful nuclear strikes.

Document 17 : Assistant Secretary of War John J. McCloy, “Memorandum of Conversation with General Marshal May 29, 1945 – 11:45 p.m.,” Top Secret

Source: Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 12, S-1

Tacitly dissenting from the Targeting Committee’s recommendations, Army Chief of Staff George Marshall argued for initial nuclear use against a clear-cut military target such as a “large naval installation.” If that did not work, manufacturing areas could be targeted, but only after warning their inhabitants. Marshall noted the “opprobrium which might follow from an ill considered employment of such force.” This document has played a role in arguments developed by Barton J. Bernstein that figures such as Marshall and Stimson were “caught between an older morality that opposed the intentional killing of non-combatants and a newer one that stressed virtually total war.” [22]  

Document 18 : “Notes of the Interim Committee Meeting Thursday, 31 May 1945, 10:00 A.M. to 1:15 P.M. – 2:15 P.M. to 4:15 P.M., ” n.d., Top Secret

Source: RG 77, MED Records, H-B files, folder no. 100 (copy from microfilm)

With Secretary of War Stimson presiding, members of the committee heard reports on a variety of Manhattan Project issues, including the stages of development of the atomic project, problems of secrecy, the possibility of informing the Soviet Union, cooperation with “like-minded” powers, the military impact of the bomb on Japan, and the problem of “undesirable scientists.” Interested in producing the “greatest psychological effect,” the Committee members agreed that the “most desirable target would be a vital war plant employing a large number of workers and closely surrounded by workers’ houses.” Exactly how the mass deaths of civilians would persuade Japanese rulers to surrender was not discussed. Bernstein has argued that this target choice represented an uneasy endorsement of “terror bombing”--the target was not exclusively military or civilian; nevertheless, worker’s housing would include non-combatant men, women, and children. [23]  It is possible that Truman was informed of such discussions and their conclusions, although he clung to a belief that the prospective targets were strictly military.

Document 19 : General George A. Lincoln to General Hull, June 4, 1945, enclosing draft, Top Secret

Source: Record Group 165, Records of the War Department General and Special Staffs, American-British-Canadian Top Secret Correspondence, Box 504, “ABC 387 Japan (15 Feb. 45)

George A. Lincoln, chief of the Strategy and Policy Group at U.S. Army’s Operations Department, commented on a memorandum by former President Herbert Hoover that Stimson had passed on for analysis. Hoover proposed a compromise solution with Japan that would allow Tokyo to retain part of its empire in East Asia (including Korea and Japan) as a way to head off Soviet influence in the region. While Lincoln believed that the proposed peace teams were militarily acceptable he doubted that they were workable or that they could check Soviet “expansion” which he saw as an inescapable result of World War II. As to how the war with Japan would end, he saw it as “unpredictable,” but speculated that “it will take Russian entry into the war, combined with a landing, or imminent threat of a landing, on Japan proper by us, to convince them of the hopelessness of their situation.” Lincoln derided Hoover’s casualty estimate of 500,000. J. Samuel Walker has cited this document to make the point that “contrary to revisionist assertions, American policymakers in the summer of 1945 were far from certain that the Soviet invasion of Manchuria would be enough in itself to force a Japanese surrender.”  [24]

Document 20 : Memorandum from R. Gordon Arneson, Interim Committee Secretary, to Mr. Harrison, June 6, 1945, Top Secret

In a memorandum to George Harrison, Stimson’s special assistant on Manhattan Project matters, Arneson noted actions taken at the recent Interim Committee meetings, including target criterion and an attack “without prior warning.”

Document 21 : Memorandum of Conference with the President, June 6, 1945, Top Secret

Source: Henry Stimson Papers, Sterling Library, Yale University (microfilm at Library of Congress)

Stimson and Truman began this meeting by discussing how they should handle a conflict with French President DeGaulle over the movement by French forces into Italian territory. (Truman finally cut off military aid to France to compel the French to pull back).  [25]  As evident from the discussion, Stimson strongly disliked de Gaulle whom he regarded as “psychopathic.” The conversation soon turned to the atomic bomb, with some discussion about plans to inform the Soviets but only after a successful test. Both agreed that the possibility of a nuclear “partnership” with Moscow would depend on “quid pro quos”: “the settlement of the Polish, Rumanian, Yugoslavian, and Manchurian problems.”

At the end, Stimson shared his doubts about targeting cities and killing civilians through area bombing because of its impact on the U.S.’s reputation as well as on the problem of finding targets for the atomic bomb. Barton Bernstein has also pointed to this as additional evidence of the influence on Stimson of an “an older morality.” While concerned about the U.S.’s reputation, Stimson did not want the Air Force to bomb Japanese cities so thoroughly that the “new weapon would not have a fair background to show its strength,” a comment that made Truman laugh.  The discussion of “area bombing” may have reminded him that Japanese civilians remained at risk from U.S. bombing operations.

III. Debates on Alternatives to First Use and Unconditional Surrender

Document 22 : Memorandum from Arthur B. Compton to the Secretary of War, enclosing “Memorandum on `Political and Social Problems,’ from Members of the `Metallurgical Laboratory’ of the University of Chicago,” June 12, 1945, Secret

Source: RG 77, MED Records, H-B files, folder no. 76 (copy from microfilm)

Physicists Leo Szilard and James Franck, a Nobel Prize winner, were on the staff of the “Metallurgical Laboratory” at the University of Chicago, a cover for the Manhattan Project program to produce fuel for the bomb. The outspoken Szilard was not involved in operational work on the bomb and General Groves kept him under surveillance but Met Lab director Arthur Compton found Szilard useful to have around. Concerned with the long-run implications of the bomb, Franck chaired a committee, in which Szilard and Eugene Rabinowitch were major contributors, that produced a report rejecting a surprise attack on Japan and recommended instead a demonstration of the bomb on the “desert or a barren island.” Arguing that a nuclear arms race “will be on in earnest not later than the morning after our first demonstration of the existence of nuclear weapons,” the committee saw international control as the alternative. That possibility would be difficult if the United States made first military use of the weapon. Compton raised doubts about the recommendations but urged Stimson to study the report. Martin Sherwin has argued that the Franck committee shared an important assumption with Truman et al.--that an “atomic attack against Japan would `shock’ the Russians”--but drew entirely different conclusions about the import of such a shock.  [26]

Document 23 : Memorandum from Acting Secretary of State Joseph Grew to the President, “Analysis of Memorandum Presented by Mr. Hoover,” June 13, 1945

Source: Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 8, Japan (After December 7/41)

A former ambassador to Japan, Joseph Grew’s extensive knowledge of Japanese politics and culture informed his stance toward the concept of unconditional surrender. He believed it essential that the United States declare its intention to preserve the institution of the emperor. As he argued in this memorandum to President Truman, “failure on our part to clarify our intentions” on the status of the emperor “will insure prolongation of the war and cost a large number of human lives.” Documents like this have played a role in arguments developed by Alperovitz that Truman and his advisers had alternatives to using the bomb such as modifying unconditional surrender and that anti-Soviet considerations weighed most heavily in their thinking. By contrast, Herbert P. Bix has suggested that the Japanese leadership would “probably not” have surrendered if the Truman administration had spelled out the status of the emperor. [27]

Document 24 : Memorandum from Chief of Staff Marshall to the Secretary of War, 15 June 1945, enclosing “Memorandum of Comments on `Ending the Japanese War,’” prepared by George A. Lincoln, June 14, 1945, Top Secret

Commenting on another memorandum by Herbert Hoover, George A. Lincoln discussed war aims, face-saving proposals for Japan, and the nature of the proposed declaration to the Japanese government, including the problem of defining “unconditional surrender.” Lincoln argued against modifying the concept of unconditional surrender: if it is “phrased so as to invite negotiation” he saw risks of prolonging the war or a “compromise peace.” J. Samuel Walker has observed that those risks help explain why senior officials were unwilling to modify the demand for unconditional surrender. [28]

Document 25 : Memorandum by J. R. Oppenheimer, “Recommendations on the Immediate Use of Nuclear Weapons,” June 16, 1945, Top Secret

In a report to Stimson, Oppenheimer and colleagues on the scientific advisory panel--Arthur Compton, Ernest O. Lawrence, and Enrico Fermi—tacitly disagreed with the report of the “Met Lab” scientists. The panel argued for early military use but not before informing key allies about the atomic project to open a dialogue on “how we can cooperate in making this development contribute to improved international relations.”

Document 26 : “Minutes of Meeting Held at the White House on Monday, 18 June 1945 at 1530,” Top Secret

Source: Record Group 218, Records of the Joint Chiefs of Staff, Central Decimal Files, 1942-1945, box 198 334 JCS (2-2-45) Mtg 186 th -194 th

With the devastating battle for Okinawa winding up, Truman and the Joint Chiefs stepped back and considered what it would take to secure Japan’s surrender. The discussion depicted a Japan that, by 1 November, would be close to defeat, with great destruction and economic losses produced by aerial bombing and naval blockade, but not ready to capitulate. Marshall believed that the latter required Soviet entry and an invasion of Kyushu, even suggesting that Soviet entry might be the “decisive action levering them into capitulation.” Truman and the Chiefs reviewed plans to land troops on Kyushu on 1 November, which Marshall believed was essential because air power was not decisive. He believed that casualties would not be more than those produced by the battle for Luzon, some 31,000. This account hints at discussion of the atomic bomb (“certain other matters”), but no documents disclose that part of the meeting.

The record of this meeting has figured in the complex debate over the estimates of casualties stemming from a possible invasion of Japan. While post-war justifications for the bomb suggested that an invasion of Japan could have produced very high levels of casualties (dead, wounded, or missing), from hundreds of thousands to a million, historians have vigorously debated the extent to which the estimates were inflated.  [29]

According to accounts based on post-war recollections and interviews, during the meeting McCloy raised the possibility of winding up the war by guaranteeing the preservation of the emperor albeit as a constitutional monarch. If that failed to persuade Tokyo, he proposed that the United States disclose the secret of the atomic bomb to secure Japan’s unconditional surrender. While McCloy later recalled that Truman expressed interest, he said that Secretary of State Byrnes squashed the proposal because of his opposition to any “deals” with Japan. Yet, according to Forrest Pogue’s account, when Truman asked McCloy if he had any comments, the latter opened up a discussion of nuclear weapons use by asking “Why not use the bomb?” [30]

Document 27 : Memorandum from R. Gordon Arneson, Interim Committee Secretary, to Mr. Harrison, June 25, 1945, Top Secret

For Harrison’s convenience, Arneson summarized key decisions made at the 21 June meeting of the Interim Committee, including a recommendation that President Truman use the forthcoming conference of allied leaders to inform Stalin about the atomic project. The Committee also reaffirmed earlier recommendations about the use of the bomb at the “earliest opportunity” against “dual targets.” In addition, Arneson included the Committee’s recommendation for revoking part two of the 1944 Quebec agreement which stipulated that the neither the United States nor Great Britain would use the bomb “against third parties without each other’s consent.” Thus, an impulse for unilateral control of nuclear use decisions predated the first use of the bomb.

Document 28 : Memorandum from George L. Harrison to Secretary of War, June 26, 1945, Top Secret

Source: RG 77, MED, H-B files, folder no. 77 (copy from microfilm)

Reminding Stimson about the objections of some Manhattan project scientists to military use of the bomb, Harrison summarized the basic arguments of the Franck report. One recommendation shared by many of the scientists, whether they supported the report or not, was that the United States inform Stalin of the bomb before it was used. This proposal had been the subject of positive discussion by the Interim Committee on the grounds that Soviet confidence was necessary to make possible post-war cooperation on atomic energy.

Document 29 : Memorandum from George L. Harrison to Secretary of War, June 28, 1945, Top Secret, enclosing Ralph Bard’s “Memorandum on the Use of S-1 Bomb,” June 27, 1945

Under Secretary of the Navy Ralph Bard joined those scientists who sought to avoid military use of the bomb; he proposed a “preliminary warning” so that the United States would retain its position as a “great humanitarian nation.” Alperovitz cites evidence that Bard discussed his proposal with Truman who told him that he had already thoroughly examined the problem of advanced warning. This document has also figured in the argument framed by Barton Bernstein that Truman and his advisers took it for granted that the bomb was a legitimate weapon and that there was no reason to explore alternatives to military use. Bernstein, however, notes that Bard later denied that he had a meeting with Truman and that White House appointment logs support that claim. [31]

Document 30 : Memorandum for Mr. McCloy, “Comments re: Proposed Program for Japan,” June 28, 1945, Draft, Top Secret

Source: RG 107, Office of Assistant Secretary of War Formerly Classified Correspondence of John J. McCloy, 1941-1945, box 38, ASW 387 Japan

Despite the interest of some senior officials such as Joseph Grew, Henry Stimson, and John J. McCloy in modifying the concept of unconditional surrender so that the Japanese could be sure that the emperor would be preserved, it remained a highly contentious subject. For example, one of McCloy’s aides, Colonel Fahey, argued against modification of unconditional surrender (see “Appendix ‘C`”).

Document 31 : Assistant Secretary of War John J. McCloy to Colonel Stimson, June 29, 1945, Top Secret

McCloy was part of a drafting committee at work on the text of a proclamation to Japan to be signed by heads of state at the forthcoming Potsdam conference. As McCloy observed the most contentious issue was whether the proclamation should include language about the preservation of the emperor: “This may cause repercussions at home but without it those who seem to know the most about Japan feel there would be very little likelihood of acceptance.”

Document 32 : Memorandum, “Timing of Proposed Demand for Japanese Surrender,” June 29, 1945, Top Secret

Probably the work of General George A. Lincoln at Army Operations, this document was prepared a few weeks before the Potsdam conference when senior officials were starting to finalize the text of the declaration that Truman, Churchill, and Chiang would issue there. The author recommended issuing the declaration “just before the bombardment program [against Japan] reaches its peak.” Next to that suggestion, Stimson or someone in his immediate office, wrote “S1”, implying that the atomic bombing of Japanese cities was highly relevant to the timing issue. Also relevant to Japanese thinking about surrender, the author speculated, was the Soviet attack on their forces after a declaration of war.

Document 33 : Stimson memorandum to The President, “Proposed Program for Japan,” 2 July 1945, Top Secret

Source: Naval Aide to the President Files, box 4, Berlin Conference File, Volume XI - Miscellaneous papers: Japan, Harry S. Truman Presidential Library

On 2 July Stimson presented to President Truman a proposal that he had worked up with colleagues in the War Department, including McCloy, Marshall, and Grew. The proposal has been characterized as “the most comprehensive attempt by any American policymaker to leverage diplomacy” in order to shorten the Pacific War. Stimson had in mind a “carefully timed warning” delivered before the invasion of Japan. Some of the key elements of Stimson’s argument were his assumption that “Japan is susceptible to reason” and that Japanese might be even more inclined to surrender if “we do not exclude a constitutional monarchy under her present dynasty.” The possibility of a Soviet attack would be part of the “threat.” As part of the threat message, Stimson alluded to the “inevitability and completeness of the destruction” which Japan could suffer, but he did not make it clear whether unconditional surrender terms should be clarified before using the atomic bomb. Truman read Stimson’s proposal, which he said was “powerful,” but made no commitments to the details, e.g., the position of the emperor.  [32]

Document 34 : Minutes, Secretary’s Staff Committee, Saturday Morning, July 7, 1945, 133d Meeting, Top Secret

Source: Record Group 353, Records of Interdepartmental and Intradepartmental Committees, Secretary’s Staff Meetings Minutes, 1944-1947 (copy from microfilm)

The possibility of modifying the concept of unconditional surrender so that it guaranteed the continuation of the emperor remained hotly contested within the U.S. government. Here senior State Department officials, Under Secretary Joseph Grew on one side, and Assistant Secretary Dean Acheson and Archibald MacLeish on the other, engaged in hot debate.

Document 35 : Combined Chiefs of Staff, “Estimate of the Enemy Situation (as of 6 July 1945, C.C.S 643/3, July 8, 1945, Secret (Appendices Not Included)

Source: RG 218, Central Decimal Files, 1943-1945, CCS 381 (6-4-45), Sec. 2 Pt. 5

This review of Japanese capabilities and intentions portrays an economy and society under “tremendous strain”; nevertheless, “the ground component of the Japanese armed forces remains Japan’s greatest military asset.” Alperovitz sees statements in this estimate about the impact of Soviet entry into the war and the possibility of a conditional surrender involving survival of the emperor as an institution as more evidence that the policymakers saw alternatives to nuclear weapons use. By contrast, Richard Frank takes note of the estimate’s depiction of the Japanese army’s terms for peace: “for surrender to be acceptable to the Japanese army it would be necessary for the military leaders to believe that it would not entail discrediting the warrior tradition and that it would permit the ultimate resurgence of a military in Japan.” That, Frank argues, would have been “unacceptable to any Allied policy maker.” [33]

Document 36 : Cable to Secretary of State from Acting Secretary Joseph Grew, July 16, 1945, Top Secret

Source: Record Group 59, Decimal Files 1945-1949, 740.0011 PW (PE)/7-1645

On the eve of the Potsdam Conference, a State Department draft of the proclamation to Japan contained language which modified unconditional surrender by promising to retain the emperor. When former Secretary of State Cordell Hull learned about it he outlined his objections to Byrnes, arguing that it might be better to wait “the climax of allied bombing and Russia’s entry into the war.” Byrnes was already inclined to reject that part of the draft, but Hull’s argument may have reinforced his decision.

Document 37 : Letter from Stimson to Byrnes, enclosing memorandum to the President, “The Conduct of the War with Japan,” 16 July 1945, Top Secret

Source: Henry L. Stimson Papers (MS 465), Sterling Library, Yale University (reel 113) (microfilm at Library of Congress)

Still interested in trying to find ways to “warn Japan into surrender,” this represents an attempt by Stimson before the Potsdam conference, to persuade Truman and Byrnes to agree to issue warnings to Japan prior to the use of the bomb. The warning would draw on the draft State-War proclamation to Japan; presumably, the one criticized by Hull (above) which included language about the emperor .  Presumably the clarified warning would be issued prior to the use of the bomb; if the Japanese persisted in fighting then “the full force of our new weapons should be brought to bear” and a “heavier” warning would be issued backed by the “actual entrance of the Russians in the war.” Possibly, as Malloy has argued, Stimson was motivated by concerns about using the bomb against civilians and cities, but his latest proposal would meet resistance at Potsdam from Byrnes and other. [34]

Document 38 : R. E. Lapp, Leo Szilard et al., “A Petition to the President of the United States,” July 17, 1945

On the eve of the Potsdam conference, Leo Szilard circulated a petition as part of a final effort to discourage military use of the bomb. Signed by about 68 Manhattan Project scientists, mainly physicists and biologists (copies with the remaining signatures are in the archival file), the petition did not explicitly reject military use, but raised questions about an arms race that military use could instigate and requested Truman to publicize detailed terms for Japanese surrender. Truman, already on his way to Europe, never saw the petition. [35]

IV. The Japanese Search for Soviet Mediation

Documents 39A-B: Magic

39A : William F. Friedman, Consultant (Armed Forces Security Agency), “A Short History of U.S. COMINT Activities,” 19 February 1952, Top Secret

39B :“Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1204 – July 12, 1945, Top Secret Ultra

Sources: A: National Security Agency Mandatory declassification review release; B: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18

Beginning in September 1940, U.S. military intelligence began to decrypt routinely, under the “Purple” code-name, the intercepted cable traffic of the Japanese Foreign Ministry. Collectively the decoded messages were known as “Magic.” How this came about is explained in an internal history of pre-war and World War II Army and Navy code-breaking activities prepared by  William F. Friedman , a central figure in the development of U.S. government cryptology during the 20 th  century. The National Security Agency kept the ‘Magic” diplomatic and military summaries classified for many years and did not release the entire series for 1942 through August 1945 until the early 1990s. [36]

The 12 July 1945 “Magic” summary includes a report on a cable from Japanese Foreign Minister Shigenori Togo to Ambassador Naotake Sato in Moscow concerning the Emperor’s decision to seek Soviet help in ending the war. Not knowing that the Soviets had already made a commitment to their Allies to declare war on Japan, Tokyo fruitlessly pursued this option for several weeks. The “Magic” intercepts from mid-July have figured in Gar Alperovitz’s argument that Truman and his advisers recognized that the Emperor was ready to capitulate if the Allies showed more flexibility on the demand for unconditional surrender. This point is central to Alperovitz’s thesis that top U.S. officials recognized a “two-step logic”: relaxing unconditional surrender and a Soviet declaration of war would have been enough to induce Japan’s surrender without the use of the bomb. [37]

Document 40 : John Weckerling, Deputy Assistant Chief of Staff, G-2, July 12, 1945, to Deputy Chief of Staff, “Japanese Peace Offer,” 13 July 1945, Top Secret Ultra

Source: RG 165, Army Operations OPD Executive File #17, Item 13 (copy courtesy of J. Samuel Walker)

The day after the Togo message was reported, Army intelligence chief Weckerling proposed several possible explanations of the Japanese diplomatic initiative. Robert J. Maddox has cited this document to support his argument that top U.S. officials recognized that Japan was not close to surrender because Japan was trying to “stave off defeat.” In a close analysis of this document, Tsuyoshi Hasegawa, who is also skeptical of claims that the Japanese had decided to surrender, argues that each of the three possibilities proposed by Weckerling “contained an element of truth, but none was entirely correct”. For example, the “governing clique” that supported the peace moves was not trying to “stave off defeat” but was seeking Soviet help to end the war. [38]

Document 41 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1205 – July 13, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18

The day after he told Sato about the current thinking on Soviet mediation, Togo requested the Ambassador to see Soviet Foreign Minister Vyacheslav Molotov and tell him of the Emperor’s “private intention to send Prince Konoye as a Special Envoy” to Moscow. Before he received Togo’s message, Sato had already met with Molotov on another matter.

Document 42 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1210 – July 17, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18.

Another intercept of a cable from Togo to Sato shows that the Foreign Minister rejected unconditional surrender and that the Emperor was not “asking the Russian’s mediation in anything like unconditional surrender.” Incidentally, this “`Magic’ Diplomatic Summary” indicates the broad scope and capabilities of the program; for example, it includes translations of intercepted French messages (see pages 8-9).

Document 43 : Admiral Tagaki Diary Entry for July 20, 1945

Source: Takashi Itoh, ed.,  Sokichi Takagi: Nikki to Joho  [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 916-917 [Translation by Hikaru Tajima]

In 1944 Navy minister Mitsumasa Yonai ordered rear admiral Sokichi Takagi to go on sick leave so that he could undertake a secret mission to find a way to end the war. Tagaki was soon at the center of a cabal of Japanese defense officials, civil servants, and academics, which concluded that, in the end, the emperor would have to “impose his decision on the military and the government.” Takagi kept a detailed account of his activities, part of which was in diary form, the other part of which he kept on index cards. The material reproduced here gives a sense of the state of play of Foreign Minister Togo’s attempt to secure Soviet mediation. Hasegawa cited it and other documents to make a larger point about the inability of the Japanese government to agree on “concrete” proposals to negotiate an end to the war. [39]

The last item discusses Japanese contacts with representatives of the Office of Strategic Services (OSS) in Switzerland. The reference to “our contact” may refer to Bank of International Settlements economist Pers Jacobbson who was in touch with Japanese representatives to the Bank as well as Gero von Gävernitz, then on the staff, but with non-official cover, of OSS station chief Allen Dulles. The contacts never went far and Dulles never received encouragement to pursue them. [40]

V. The Trinity Test

Document 44 : Letter from Commissar of State Security First Rank, V. Merkulov, to People’s Commissar for Internal Affairs L. P. Beria, 10 July 1945, Number 4305/m, Top Secret (translation by Anna Melyaskova)

Source:  L.D. Riabev, ed.,  Atomnyi Proekt SSSR  (Moscow: izd MFTI, 2002), Volume 1, Part 2, 335-336

This 10 July 1945 letter from NKVD director V. N. Merkulov to Beria is an example of Soviet efforts to collect inside information on the Manhattan Project, although not all the detail was accurate. Merkulov reported that the United States had scheduled the test of a nuclear device for that same day, although the actual test took place 6 days later. According to Merkulov, two fissile materials were being produced: element-49 (plutonium), and U-235; the test device was fueled by plutonium. The Soviet source reported that the weight of the device was 3 tons (which was in the ball park) and forecast an explosive yield of 5 kilotons. That figure was based on underestimates by Manhattan Project scientists: the actual yield of the test device was 20 kilotons.

As indicated by the L.D. Riabev’s notes, it is possible that Beria’s copy of this letter ended up in Stalin’s papers. That the original copy is missing from Beria’s papers suggests that he may have passed it on to Stalin before the latter left for the Potsdam conference. [41]

Document 45 : Telegram War [Department] 33556, from Harrison to Secretary of War, July 17, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File 5e (copy from microfilm)

An elated message from Harrison to Stimson reported the success of the  Trinity Test  of a plutonium implosion weapon. The light from the explosion could been seen “from here [Washington, D.C.] to “high hold” [Stimson’s estate on Long Island—250 miles away]” and it was so loud that Harrison could have heard the “screams” from Washington, D.C. to “my farm” [in Upperville, VA, 50 miles away] [42]

Document 46 : Memorandum from General L. R. Groves to Secretary of War, “The Test,” July 18, 1945, Top Secret, Excised Copy

Source: RG 77, MED Records, Top Secret Documents, File no. 4 (copy from microfilm)

General Groves prepared for Stimson, then at Potsdam, a detailed account of the Trinity test. [43]

VI. The Potsdam Conference

Document 47 : Truman’s Potsdam Diary

Source: Barton J. Bernstein, “Truman at Potsdam: His Secret Diary,”  Foreign Service Journal , July/August 1980, excerpts, used with author’s permission. [44]

Some years after Truman’s death, a hand-written diary that he kept during the Potsdam conference surfaced in his personal papers. For convenience, Barton Bernstein’s rendition is provided here but linked here are the scanned versions of Truman’s handwriting on the National Archives’ website (for 15-30 July).

The diary entries cover July 16, 17, 18, 20, 25, 26, and 30 and include Truman’s thinking about a number of issues and developments, including his reactions to Churchill and Stalin, the atomic bomb and how it should be targeted, the possible impact of the bomb and a Soviet declaration of war on Japan, and his decision to tell Stalin about the bomb. Receptive to pressure from Stimson, Truman recorded his decision to take Japan’s “old capital” (Kyoto) off the atomic bomb target list. Barton Bernstein and Richard Frank, among others, have argued that Truman’s assertion that the atomic targets were “military objectives” suggested that either he did not understand the power of the new weapons or had simply deceived himself about the nature of the targets. Another statement—“Fini Japs when that [Soviet entry] comes about”—has also been the subject of controversy over whether it meant that Truman thought it possible that the war could end without an invasion of Japan. [45]

Document 48 : Stimson Diary entries for July 16 through 25, 1945

Stimson did not always have Truman’s ear, but historians have frequently cited his diary when he was at the Potsdam conference. There Stimson kept track of S-1 developments, including news of the successful first test (see entry for July 16) and the ongoing deployments for nuclear use against Japan. When Truman received a detailed account of the test, Stimson reported that the “President was tremendously pepped up by it” and that “it gave him an entirely new feeling of confidence” (see entry for July 21). Whether this meant that Truman was getting ready for a confrontation with Stalin over Eastern Europe and other matters has also been the subject of debate.

An important question that Stimson discussed with Marshall, at Truman’s request, was whether Soviet entry into the war remained necessary to secure Tokyo’s surrender. Marshall was not sure whether that was so although Stimson privately believed that the atomic bomb would provide enough to force surrender (see entry for July 23). This entry has been cited by all sides of the controversy over whether Truman was trying to keep the Soviets out of the war. [46]  During the meeting on August 24, discussed above, Stimson gave his reasons for taking Kyoto off the atomic target list: destroying that city would have caused such “bitterness” that it could have become impossible “to reconcile the Japanese to us in that area rather than to the Russians.” Stimson vainly tried to preserve language in the Potsdam Declaration designed to assure the Japanese about “the continuance of their dynasty” but received Truman’s assurance that such a consideration could be conveyed later through diplomatic channels (see entry for July 24). Hasegawa argues that Truman realized that the Japanese would refuse a demand for unconditional surrender without a proviso on a constitutional monarchy and that “he needed Japan’s refusal to justify the use of the atomic bomb.” [47]

Document 49 : Walter Brown Diaries, July 10-August 3, 1945

Source: Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 10, folder 12, Byrnes, James F.: Potsdam, Minutes, July-August 1945

Walter Brown, who served as special assistant to Secretary of State Byrnes, kept a diary which provided considerable detail on the Potsdam conference and the growing concerns about Soviet policy among top U.S. officials. This document is a typed-up version of the hand-written original (which Brown’s family has provided to Clemson University). That there may be a difference between the two sources becomes evident from some of the entries; for example, in the entry for July 18, 1945 Brown wrote: "Although I knew about the atomic bomb when I wrote these notes, I dared not place it in writing in my book.”

The degree to which the typed-up version reflects the original is worth investigating. In any event, historians have used information from the diary to support various interpretations. For example, Bernstein cites the entries for 20 and 24 July to argue that “American leaders did not view Soviet entry as a substitute for the bomb” but that the latter “would be so powerful, and the Soviet presence in Manchuria so militarily significant, that there was no need for actual Soviet intervention in the war.” For  Brown's diary entry of 3 August 9 1945 historians have developed conflicting interpretations (See discussion of document 57). [48]

Document 50 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1214 – July 22, 1945, Top Secret Ultra

This “Magic” summary includes messages from both Togo and Sato. In a long and impassioned message, the latter argued why Japan must accept defeat: “it is meaningless to prove one’s devotion [to the Emperor] by wrecking the State.” Togo rejected Sato’s advice that Japan could accept unconditional surrender with one qualification: the “preservation of the Imperial House.” Probably unable or unwilling to take a soft position in an official cable, Togo declared that “the whole country … will pit itself against the enemy in accordance with the Imperial Will as long as the enemy demands unconditional surrender.”

Document 51 : Forrestal Diary Entry, July 24, 1945, “Japanese Peace Feelers”

Source: Naval Historical Center, Operational Archives, James Forrestal Diaries

Secretary of the Navy James Forrestal was a regular recipient of “Magic” intercept reports; this substantial entry reviews the dramatic Sato-Togo exchanges covered in the 22 July “Magic” summary (although Forrestal misdated Sato’s cable as “first of July” instead of the 21 st ). In contrast to Alperovitz’s argument that Forrestal tried to modify the terms of unconditional surrender to give the Japanese an out, Frank sees Forrestal’s account of the Sato-Togo exchange as additional evidence that senior U.S. officials understood that Tokyo was not on the “cusp of surrender.”  [49]

Document 52 : Davies Diary entry for July 29, 1945

S ource: Joseph E. Davies Papers, Library of Congress, Manuscripts Division, box 19, 29 July 1945

Having been asked by Truman to join the delegation to the Potsdam conference, former-Ambassador Davies sat at the table with the Big Three throughout the discussions. This diary entry has figured in the argument that Byrnes believed that the atomic bomb gave the United States a significant advantage in negotiations with the Soviet Union. Plainly Davies thought otherwise. [50]

VII. Debates among the Japanese – Late July/Early August 1945

Document 53 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1221- July 29, 1945, Top Secret Ultra

In the  Potsdam Declaration  the governments of China, Great Britain, and the United States) demanded the “unconditional surrender of all Japanese armed forces. “The alternative is prompt and utter destruction.” The next day, in response to questions from journalists about the government’s reaction to the ultimatum, Prime Minister Suzuki apparently said that “We can only ignore [ mokusatsu ] it. We will do our utmost to complete the war to the bitter end.” That, Bix argues, represents a “missed opportunity” to end the war and spare the Japanese from continued U.S. aerial attacks. [51]  Togo’s private position was more nuanced than Suzuki’s; he told Sato that “we are adopting a policy of careful study.” That Stalin had not signed the declaration (Truman and Churchill did not ask him to) led to questions about the Soviet attitude. Togo asked Sato to try to meet with Soviet Foreign Minister Molotov as soon as possible to “sound out the Russian attitude” on the declaration as well as Japan’s end-the-war initiative. Sato cabled Togo earlier that he saw no point in approaching the Soviets on ending the war until Tokyo had “concrete proposals.” “Any aid from the Soviets has now become extremely doubtful.”

Document 54 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1222 – July 30, 1945, Top Secret Ultra

This report included an intercept of a message from Sato reporting that it was impossible to see Molotov and that unless the Togo had a “concrete and definite plan for terminating the war” he saw no point in attempting to meet with him.

Document 55 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1225 – August 2, 1945, Top Secret Ultra

An intercepted message from Togo to Sato showed that Tokyo remained interested in securing Moscow’s good office but that it “is difficult to decide on concrete peace conditions here at home all at once.” “[W]e are exerting ourselves to collect the views of all quarters on the matter of concrete terms.” Barton Bernstein, Richard Frank, and Tsuyoshi Hasegawa, among others, have argued that the “Magic” intercepts from the end of July and early August show that the Japanese were far from ready to surrender. According to Herbert Bix, for months Hirohito had believed that the “outlook for a negotiated peace could be improved if Japan fought and won one last decisive battle,” thus, he delayed surrender, continuing to “procrastinate until the bomb was dropped and the Soviets attacked.” [52]

Document 56 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1226 - August 3, 1945, Top Secret Ultra

This summary included intercepts of Japanese diplomatic reporting on the Soviet buildup in the Far East as well as a naval intelligence report on Anglo-American discussions of U.S. plans for the invasion of Japan. Part II of the summary includes the rest of Togo’s 2 August cable which instructed Sato to do what he could to arrange an interview with Molotov.

Document 57 : Walter Brown Meeting Notes, August 3, 1945

Historians have used this item in the papers of Byrne’s aide, Walter Brown, to make a variety of points. Richard Frank sees this brief discussion of Japan’s interest in Soviet diplomatic assistance as crucial evidence that Admiral Leahy had been sharing “MAGIC” information with President Truman. He also points out that Truman and his colleagues had no idea what was behind Japanese peace moves, only that Suzuki had declared that he would “ignore” the Potsdam Declaration. Alperovitz, however, treats it as additional evidence that “strongly suggests” that Truman saw alternatives to using the bomb. [53]

Document 58 : “Magic” – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 502, 4 August 1945

Source: RG 457, Summaries of Intercepted Japanese Messages (“Magic” Far East Summary, March 20, 1942 – October 2, 1945), box 7, SRS 491-547

This “Far East Summary” included reports on the Japanese Army’s plans to disperse fuel stocks to reduce vulnerability to bombing attacks, the text of a directive by the commander of naval forces on “Operation Homeland,” the preparations and planning to repel a U.S. invasion of Honshu, and the specific identification of army divisions located in, or moving into, Kyushu. Both Richard Frank and Barton Bernstein have used intelligence reporting and analysis of the major buildup of Japanese forces on southern Kyushu to argue that U.S. military planners were so concerned about this development that by early August 1945 they were reconsidering their invasion plans. [54]

Document 59 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1228 – August 5, 1945, Top Secret Ultra

This summary included several intercepted messages from Sato, who conveyed his despair and exasperation over what he saw as Tokyo’s inability to develop terms for ending the war: “[I]f the Government and the Military dilly-dally in bringing this resolution to fruition, then all Japan will be reduced to ashes.” Sato remained skeptical that the Soviets would have any interest in discussions with Tokyo: “it is absolutely unthinkable that Russia would ignore the Three Power Proclamation and then engage in conversations with our special envoy.”

VIII. The Execution Order

Documents 60a-d: Framing the Directive for Nuclear Strikes:

60A . Cable VICTORY 213 from Marshall to Handy, July 22, 1945, Top Secret

60B . Memorandum from Colonel John Stone to General Arnold, “Groves Project,” 24 July 1945, Top Secret

60C . Cable WAR 37683 from General Handy to General Marshal, enclosing directive to General Spatz, July 24, 1945, Top Secret

60D . Cable VICTORY 261 from Marshall to General Handy, July 25, 1945, 25 July 1945, Top Secret

60E . General Thomas T. Handy to General Carl Spaatz, July 26, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, Files no. 5b and 5e ((copies from microfilm)

Top Army Air Force commanders may not have wanted to take responsibility for the first use of nuclear weapons on urban targets and sought formal authorization from Chief of Staff Marshall who was then in Potsdam. [55]  On 22 July Marshall asked Deputy Chief of Staff Thomas Handy to prepare a draft; General Groves wrote one which went to Potsdam for Marshall’s approval. Colonel John Stone, an assistant to commanding General of the Army Air Forces Henry H. “Hap” Arnold, had just returned from Potsdam and updated his boss on the plans as they had developed. On 25 July Marshall informed Handy that Secretary of War Stimson had approved the text; that same day, Handy signed off on a directive which ordered the use of atomic weapons on Japan, with the first weapon assigned to one of four possible targets—Hiroshima, Kokura, Niigata, or Nagasaki. “Additional bombs will be delivery on the [targets] as soon as made ready by the project staff.”

Document 61 : Memorandum from Major General L. R. Groves to Chief of Staff, July 30, 1945, Top Secret, Sanitized Copy

Source: RG 77, MED Records, Top Secret Documents, File no. 5

With more information on the Alamogordo test available, Groves provided Marshall with detail on the destructive power of atomic weapons. Barton J. Bernstein has observed that Groves’ recommendation that troops could move into the “immediate explosion area” within a half hour demonstrates the prevalent lack of top-level knowledge of the dangers of nuclear weapons effects. [56]  Groves also provided the schedule for the delivery of the weapons: the components of the gun-type bomb to be used on Hiroshima had arrived on Tinian, while the parts of the second weapon to be dropped were leaving San Francisco. By the end of November over ten weapons would be available, presumably in the event the war had continued.

Documents 62A-C: Weather delays

62A . CG 313 th  Bomb Wing, Tinian cable APCOM 5112 to War Department, August 3, 1945, Top Secret

62B . CG 313 th  Bomb Wing, Tinian cable APCOM 5130 to War Department, August 4, 1945, Top Secret

62C . CG 313 th  Bomb Wing, Tinian cable APCOM 5155 to War Department, August 4, 1945, Top Secret

Source: RG 77, Tinian Files, April-December 1945, box 21 (copies courtesy of Barton Bernstein)

The Hiroshima “operation” was originally slated to begin in early August depending on local conditions. As these cables indicate, reports of unfavorable weather delayed the plan. The second cable on 4 August shows that the schedule advanced to late in the evening of 5 August. The handwritten transcriptions are on the original archival copies.

IX. The First Nuclear Strikes and their Impact

Document 63 : Memorandum from General L. R. Groves to the Chief of Staff, August 6, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5b (copy from microfilm)

Two days after the bombing of Hiroshima, Groves provided Chief of Staff Marshall with a report which included messages from Captain William S. Parsons and others about the impact of the detonation which, through prompt radiation effects, fire storms, and blast effects, immediately killed at least 70,000, with many dying later from radiation sickness and other causes. [57]

How influential the atomic bombings of Hiroshima and later Nagasaki compared to the impact of the Soviet declaration of war were to the Japanese decision to surrender has been the subject of controversy among historians. Sadao Asada emphasizes the shock of the atomic bombs, while Herbert Bix has suggested that Hiroshima and the Soviet declaration of war made Hirohito and his court believe that failure to end the war could lead to the destruction of the imperial house. Frank and Hasegawa divide over the impact of the Soviet declaration of war, with Frank declaring that the Soviet intervention was “significant but not decisive” and Hasegawa arguing that the two atomic bombs “were not sufficient to change the direction of Japanese diplomacy. The Soviet invasion was.” [58]

Document 64 : Walter Brown Diary Entry, 6 August 1945

Source:  Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 68, folder 13, “Transcript/Draft B

Returning from the Potsdam Conference, sailing on the  U.S.S. Augusta , Truman learned about the atomic bombing of Hiroshima and announced it twice, first to those in the wardroom (socializing/dining area for commissioned officers), and then to the sailors’ mess. Still unaware of radiation effects, Truman emphasized the explosive yield. Later, he met with Secretary of State Byrnes and they discussed the Manhattan Project’s secrecy and the huge expenditures. Truman, who had been chair of the Senate Special Committee to Investigate the National Defense Program, said that “only on the appeal of Secretary of War Stimson did he refrain and let the War Department continue with the experiment unmolested.”

Document 65 : Directive from the Supreme Command Headquarters to the Commander-in-Chief of the Soviet Forces in the Far East on the Start of Combat Operations, No. 11122, Signed by [Communist Party General Secretary Joseph] Stalin and [Chief of General Staff A.I.] Antonov, 7 August 1945 (translation by Anna Melyakova)

Source: V. A. Zolotarev, ed.,  Sovetsko-Iaponskaia Voina 1945 Goda: Istoriia Voenno-Politicheskogo Protivoborstva Dvukh Derzhav v 30–40e Gody ( Moscow: Terra, 1997 and 2000), Vol. 7 (1), 340-341.

To keep his pledge at Yalta to enter the war against Japan and to secure the territorial concessions promised at the conference (e.g., Soviet annexation of the Kuriles and southern Sakhalin and a Soviet naval base at Port Arthur, etc.) Stalin considered various dates to schedule an attack. By early August he decided that 9-10 August 1945 would be the best dates for striking Japanese forces in Manchuria. In light of Japan’s efforts to seek Soviet mediation, Stalin wanted to enter the war quickly lest Tokyo reach a compromise peace with the Americans and the British at Moscow’s expense. But on 7 August, Stalin changed the instructions: the attack was to begin the next day. According to David Holloway, “it seems likely that the atomic bombing of Hiroshima the day before that impelled [Stalin] to speed up Soviet entry into the war” and “secure the gains promised at Yalta.” [59]

Document 66 : Memorandum of Conversation, “Atomic Bomb,” August 7, 1945

Source: Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 5-9, 1945.

The Soviets already knew about the U.S. atomic project from espionage sources in the United States and Britain so Molotov’s comment to Ambassador Harriman about the secrecy surrounding the U.S. atomic project can be taken with a grain of salt, although the Soviets were probably unaware of specific plans for nuclear use.

Documents 67A-B:  Early High-level Reactions to the Hiroshima Bombing

67A : Cabinet Meeting and Togo's Meeting with the Emperor, August 7-8, 1945 Source: Gaimusho (Ministry of Foreign Affairs) ed.  Shusen Shiroku  (The Historical Records of the End of the War), annotated by Jun Eto, volume 4, 57-60 [Excerpts] [Translation by Toshihiro Higuchi]

67B : Admiral Tagaki Diary Entry for Wednesday, August 8 , 1945

Source: Takashi Itoh, ed.,  Sokichi Takagi: Nikki to Joho  [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 923-924 [Translation by Hikaru Tajima]

Excerpts from the Foreign Ministry's compilation about the end of the war show how news of the bombing reached Tokyo as well as how Foreign Minister's Togo initially reacted to reports about Hiroshima. When he learned of the atomic bombing from the Domei News Agency, Togo believed that it was time to give up and advised the cabinet that the atomic attack provided the occasion for Japan to surrender on the basis of the Potsdam Declaration. Togo could not persuade the cabinet, however, and the Army wanted to delay any decisions until it had learned what had happened to Hiroshima. When the Foreign Minister met with the Emperor, Hirohito agreed with him; he declared that the top priority was an early end to the war, although it would be acceptable to seek better surrender terms--probably U.S. acceptance of a figure-head emperor--if it did not interfere with that goal. In light of those instructions, Togo and Prime Minister Suzuki agreed that the Supreme War Council should meet the next day.  [59a]

An entry from Admiral Tagaki's diary for August 8 conveys more information on the mood in elite Japanese circles after Hiroshima, but before the Soviet declaration of war and the bombing of Nagasaki. Seeing the bombing of Hiroshima as a sign of a worsening situation at home, Tagaki worried about further deterioration. Nevertheless, his diary suggests that military hard-liners were very much in charge and that Prime Minister Suzuki was talking tough against surrender, by evoking last ditch moments in Japanese history and warning of the danger that subordinate commanders might not obey surrender orders. The last remark aggravated Navy Minister Yonai who saw it as irresponsible. That the Soviets had made no responses to Sato's request for a meeting was understood as a bad sign; Yonai realized that the government had to prepare for the possibility that Moscow might not help. One of the visitors mentioned at the beginning of the entry was Iwao Yamazaki who became Minister of the Interior in the next cabinet.

Document 68 : Navy Secretary James Forrestal to President Truman, August 8, 1945

General Douglas MacArthur had been slated as commander for military operations against Japan’s mainland, this letter to Truman from Forrestal shows that the latter believed that the matter was not settled. Richard Frank sees this as evidence of the uncertainty felt by senior officials about the situation in early August; Forrestal would not have been so “audacious” to take an action that could ignite a “political firestorm” if he “seriously thought the end of the war was near.”

Document 69 : Memorandum of Conversation, “Far Eastern War and General Situation,” August 8, 1945, Top Secret

Source: Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 5-9, 1945

Shortly after the Soviets declared war on Japan, in line with commitments made at the Yalta and Potsdam conferences, Ambassador Harriman met with Stalin, with George Kennan keeping the U.S. record of the meeting. After Stalin reviewed in considerable detail, Soviet military gains in the Far East, they discussed the possible impact of the atomic bombing on Japan’s position (Nagasaki had not yet been attacked) and the dangers and difficulty of an atomic weapons program. According to Hasegawa, this was an important, even “startling,” conversation: it showed that Stalin “took the atomic bomb seriously”; moreover, he disclosed that the Soviets were working on their own atomic program. [60]

Document 70 : Entries for 8-9 August, Robert P. Meiklejohn Diary

Source: W.A. Harriman Papers, Library of Congress, box 211 , Robert Pickens Meiklejohn World War II Diary At London and Moscow March 10, 1941-February 14, 1946 , Volume II (Privately printed, 1980 [Printed from hand-written originals]) (Reproduced with permission)

Robert P. Meiklejohn, who worked as Ambassador W. A. Harriman’s administrative assistant at the U.S. Embassies in Moscow and London during and after World War II, kept a detailed diary of his experiences and observations. The entries for 8 and 9 August, prepared in light of the bombing of Hiroshima, include discussion of the British contribution to the Manhattan Project, Harriman (“his nibs’”) report on his meeting with Molotov about the Soviet declaration of war, and speculation about the impact of the bombing of Hiroshima on the Soviet decision. According to Meiklejohn, “None of us doubt that the atomic bomb speeded up the Soviets’ declaration of war.”

Document 71 : Memorandum of Conference with the President, August 8, 1945 at 10:45 AM

At their first meeting after the dropping of the bomb on Hiroshima, Stimson briefed Truman on the scale of the destruction, with Truman recognizing the “terrible responsibility” that was on his shoulders. Consistent with his earlier attempts, Stimson encouraged Truman to find ways to expedite Japan’s surrender by using “kindness and tact” and not treating them in the same way as the Germans. They also discussed postwar legislation on the atom and the pending Henry D. Smyth report on the scientific work underlying the Manhattan project and postwar domestic controls of the atom.

Documents 72A-C: The Attack on Nagasaki:

72A . Cable APCOM 5445 from General Farrell to O’Leary [Groves assistant], August 9, 1945, Top Secret

72B . COMGENAAF 8 cable CMDW 576 to COMGENUSASTAF, for General Farrell, August 9, 1945, Top secret

72C . COMGENAAF 20 Guam cable AIMCCR 5532 to COMGENUSASTAF Guam, August 10, 1945, Top Secret

Source: RG 77, Tinian Files, April-December 1945, box 20, Envelope G Tinian Files, Top Secret

The prime target for the second atomic attack was Kokura, which had a large army arsenal and ordnance works, but various problems ruled that city out; instead, the crew of the B-29 that carried “Fat Man” flew to an alternate target at Nagasaki. These cables are the earliest reports of the mission; the bombing of Nagasaki killed immediately at least 39,000 people, with more dying later. According to Frank, the “actual total of deaths due to the atomic bombs will never be known,” but the “huge number” ranges somewhere between 100,000 and 200,000 people. Barton J. Bernstein and Martin Sherwin have argued that if top Washington policymakers had kept tight control of the delivery of the bomb instead of delegating it to Groves the attack on Nagasaki could have been avoided. The combination of the first bomb and the Soviet declaration of war would have been enough to induce Tokyo’s surrender. By contrast, Maddox argues that Nagasaki was necessary so that Japanese “hardliners” could not “minimize the first explosion” or otherwise explain it away. [61]

Documents 73A-B: Ramsey Letter from Tinian Island

73A : Letter from Norman Ramsey to J. Robert Oppenheimer, undated [mid-August 1945], Secret, excerpts Source: Library of Congress, J. Robert Oppenheimer Papers, box 60, Ramsey, Norman

73B : Transcript of the letter prepared by editor.

Ramsey, a physicist, served as deputy director of the bomb delivery group, Project Alberta. This personal account, written on Tinian, reports his fears about the danger of a nuclear accident, the confusion surrounding the Nagasaki attack, and early Air Force thinking about a nuclear strike force.

X. Toward Surrender

Document 74 : “Magic” – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 507, August 9, 1945

Within days after the bombing of Hiroshima, U.S. military intelligence intercepted Japanese reports on the destruction of the city. According to an “Eyewitness Account (and Estimates Heard) … In Regard to the Bombing of Hiroshima”: “Casualties have been estimated at 100,000 persons.”

Document 75 : “Hoshina Memorandum” on the Emperor’s “Sacred Decision [ go-seidan] ,” 9-10 August, 1945

Source: Zenshiro Hoshina,  Daitoa Senso Hishi: Hoshina Zenshiro Kaiso-roku  [Secret History of the Greater East Asia War: Memoir of Zenshiro Hoshina] (Tokyo, Japan: Hara-Shobo, 1975), excerpts from Section 5, “The Emperor made  go-seidan  [= the sacred decision] – the decision to terminate the war,” 139-149 [translation by Hikaru Tajima]

Despite the bombing of Hiroshima, the Soviet declaration of war, and growing worry about domestic instability, the Japanese cabinet (whose decisions required unanimity) could not form a consensus to accept the Potsdam Declaration. Members of the Supreme War Council—“the Big Six” [62] —wanted the reply to Potsdam to include at least four conditions (e.g., no occupation, voluntary disarmament); they were willing to fight to the finish. The peace party, however, deftly maneuvered to break the stalemate by persuading a reluctant emperor to intervene. According to Hasegawa, Hirohito had become convinced that the preservation of the monarchy was at stake. Late in the evening of 9 August, the emperor and his advisers met in the bomb shelter of the Imperial Palace.

Zenshiro Hoshina, a senior naval official, attended the conference and prepared a detailed account. With Prime Minister Suzuki presiding, each of the ministers had a chance to state their views directly to Hirohito. While Army Minister Anami tacitly threatened a coup (“civil war”), the emperor accepted the majority view that the reply to the Potsdam declaration should include only one condition not the four urged by “Big Six.” Nevertheless, the condition that Hirohito accepted was not the one that foreign minister Togo had brought to the conference. What was at stake was the definition of the  kokutai  (national policy). Togo’s proposal would have been generally consistent with a constitutional monarchy because it defined the  kokutai  narrowly as the emperor and the imperial household. What Hirohito accepted, however, was a proposal by the extreme nationalist Kiichiro Hiranuma which drew upon prevailing understandings of the  kokutai : the “mythical notion” that the emperor was a living god. “This was the affirmation of the emperor’s theocratic powers, unencumbered by any law, based on Shinto gods in antiquity, and totally incompatible with a constitutional monarchy.” Thus, the Japanese response to the Potsdam declaration opposed “any demand which prejudices the prerogatives of his Majesty as a sovereign ruler.” This proved to be unacceptable to the Truman administration. [63]

Document 76 :“Magic’ – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 508, August 10, 1945

More intercepted messages on the bombing of Hiroshima.

Documents 77A-B: The First Japanese Offer Intercepted

77A . “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1233 – August 10, 1945, Top Secret Ultra

77B . Translation of intercepted Japanese messages, circa 10 August 10, 1945, Top Secret Ultra

The first Japanese surrender offer was intercepted shortly before Tokyo broadcast it. This issue of the diplomatic summary also includes Togo’s account of his notification of the Soviet declaration of war, reports of Soviet military operations in the Far East, and intercepts of French diplomatic traffic. A full translation of the surrender offer was circulated separately. The translations differ but they convey the sticking point that prevented U.S. acceptance: Tokyo’s condition that the allies not make any “demand which prejudices the prerogatives of His Majesty as a sovereign ruler.”

Document 78 : Diary Entry, Friday, August 10, 1945, Henry Wallace Diary

Source: Papers of Henry A. Wallace, Special Collections Department, University of Iowa Libraries, Iowa City, Iowa (copy courtesy of Special Collections Department)

Note: The second page of the diary entry includes a newspaper clipping of the Associated Press’s transmission of the Byrnes note. Unfortunately, AP would not authorize the Archive to reproduce this item without payment. Therefore, we are publishing an excised version of the entry, with a link to the  Byrnes note .

Secretary of Commerce (and former Vice President) Henry Wallace provided a detailed report on the cabinet meeting where Truman and his advisers discussed the Japanese surrender offer, Russian moves into Manchuria, and public opinion on “hard” surrender terms. With Japan close to capitulation, Truman asserted presidential control and ordered a halt to atomic bombings. Barton J. Bernstein has suggested that Truman’s comment about “all those kids” showed his belated recognition that the bomb caused mass casualties and that the target was not purely a military one. [64]

Document 79 : Entries for 10-11 August, Robert P. Meiklejohn Diary

In these entries, Meiklejohn discussed how he and others in the Moscow Embassy learned about the bombing of Nagasaki from the “OWI Bulletin.” Entries for 10 and 11 August cover discussion at the Embassy about the radio broadcast announcing that Japan would surrender as long the Emperor’s status was not affected. Harriman opined that “surrender is in the bag” because of the Potsdam Declaration’s provision that the Japanese could “choose their own form of government, which would probably include the Emperor.” Further, “the only alternative to the Emperor is Communism,” implying that an official role for the Emperor was necessary to preserve social stability and prevent social revolution.

Document 80 : Stimson Diary Entries, Friday and Saturday, August 10 and 11, 1945

Stimson’s account of the events of 10 August focused on the debate over the reply to the Japanese note, especially the question of the Emperor’s status.  The U.S. reply , drafted during the course of the day, did not explicitly reject the note but suggested that any notion about the “prerogatives” of the Emperor would be superceded by the concept that all Japanese would be “Subject to the Supreme Commander of the Allied Powers.” The language was ambiguous enough to enable Japanese readers, upon Hirohito’s urging, to believe that they could decide for themselves the Emperor’s future role. Stimson accepted the language believing that a speedy reply to the Japanese would allow the United States to “get the homeland into our hands before the Russians could put in any substantial claim to occupy and help rule it.” If the note had included specific provision for a constitutional monarchy, Hasegawa argues, it would have “taken the wind out of the sails” of the military faction and Japan might have surrendered several days earlier, on August 11 or 12 instead of August 14. [65]

Document 81 : Entries from Walter Brown Diary, 10-11 August 1945

Source:  Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter Brown Papers, box 68, folder 13, “Transcript/Draft B

Brown recounted Byrnes’ debriefing of the 10 August White House meeting on the Japanese peace offer, an account which differed somewhat from that in the Stimson diary .  According to what Byrnes told Brown, Truman, Stimson, and Leahy favored accepting the Japanese note, but Byrnes objected that the United States should “go [no] further than we were willing to go at Potsdam.” Stimson’s account of the meeting noted Byrnes’ concerns (“troubled and anxious”) about the Japanese note and implied that he (Stimson) favored accepting it, but did not picture the debate as starkly as Browns's did.

Document 82 : General L. R. Groves to Chief of Staff George C. Marshall,  August 10, 1945, Top Secret, with a hand-written note by General Marshall

Source: George C. Marshall Papers, George C. Marshall Library, Lexington, VA (copy courtesy of Barton J. Bernstein)

Groves informed General Marshall that he was making plans for the use of a third atomic weapon sometime after 17 August, depending on the weather. With Truman having ordered a halt to the atomic bombings [See document 78], Marshall wrote on Grove's memo that the bomb was “not to be released over Japan without express authority from the President.”

Document 83 : Memorandum of Conversation, “Japanese Surrender Negotiations,” August 10, 1945, Top Secret

Source: Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 10-12, 1945

Japan’s prospective surrender was the subject of detailed discussion between Harriman, British Ambassador Kerr, and Soviet Foreign Minister Molotov during the evening of August 10 (with a follow-up meeting occurring at 2 a.m.). In the course of the conversation, Harriman received a message from Washington that included the proposed U.S. reply and a request for Soviet support of the reply. After considerable pressure from Harriman, the Soviets signed off on the reply but not before tensions surfaced over the control of Japan--whether Moscow would have a Supreme Commander there as well. This marked the beginning of a U.S.-Soviet “tug of war” over occupation arrangements for Japan. [66]

Document 84 : Admiral Tagaki Diary Entry for 12 August [1945] Source: Takashi Itoh, ed.,  Sokichi Takagi: Nikki to Joho  [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 926-927 [Translation by Hikaru Tajima]

As various factions in the government maneuvered on how to respond to the Byrnes note, Navy Minister Yonai and Admiral Tagaki discussed the latest developments. Yonai was upset that Chief of Staff Yoshijiro Umezu and naval chief Suemu Toyada had sent the emperor a memorandum arguing that acceptance of the Brynes note would “desecrate the emperor’s dignity” and turn Japan into virtually a “slave nation.” The emperor chided Umezu and Toyoda for drawing hasty conclusions; in this he had the support of Yonai, who also dressed them down. As Yonai explained to Tagaki, he had also confronted naval vice Chief Takijiro Onishi to make sure that he obeyed any decision by the Emperor. Yonai made sure that Takagi understood his reasons for bringing the war to an end and why he believed that the atomic bomb and the Soviet declaration of war had made it easier for Japan to surrender. [67]

Document 85 : Memorandum from Major General Clayton Bissell, Assistant Chief of Staff, G-2, for the Chief of Staff, “Estimate of Japanese Situation for Next 30 Days,” August 12, 1945, Top Secret

Source: National Archives, RG 165, Army Operations OPD, Executive Files 1940-1945, box 12, Exec #2

Not altogether certain that surrender was imminent, Army intelligence did not rule out the possibility that Tokyo would try to “drag out the negotiations” or reject the Byrnes proposal and continue fighting. If the Japanese decided to keep fighting, G-2 opined that “Atomic bombs will not have a decisive effect in the next 30 days.” Richard Frank has pointed out that this and other documents indicate that high level military figures remained unsure as to how close Japan really was to surrender.

Document 86 : The Cabinet Meeting over the Reply to the Four Powers (August 13)

Source:  Gaimusho [Ministry of Foreign Affairs], ed., Shusen Shiroku [Historical Record of the End of the War] (Tokyo: Hokuyosha, 1977-1978), vol. 5, 27-35 [Translated by Toshihiro Higuchi]

The Byrnes Note did not break the stalemate at the cabinet level. An account of the cabinet debates on August 13 prepared by Information Minister Toshiro Shimamura showed the same divisions as before; Anami and a few other ministers continued to argue that the Allies threatened the  kokutai  and that setting the four conditions (no occupation, etc.) did not mean that the war would continue. Nevertheless, Anami argued, “We are still left with some power to fight.” Suzuki, who was working quietly with the peace party, declared that the Allied terms were acceptable because they gave a “dim hope in the dark” of preserving the emperor. At the end of the meeting, he announced that he would report to Hirohito and ask him to make another “Sacred Judgment”. Meanwhile, junior Army officers plotted a coup to thwart the plans for surrender. [68]

Document 87 : Telephone conversation transcript, General Hull and Colonel Seaman [sic] – 1325 – 13 Aug 45, Top Secret

Source: George C. Marshall Library, Lexington, VA, George C. Marshall Papers (copy courtesy of Barton J. Bernstein)

While Truman had rescinded the order to drop nuclear bombs, the war was not yet over and uncertainty about Japan’s next step motivated war planner General John E. Hull (assistant chief of staff for the War Department’s Operations Division), and one of Groves’ associates, Colonel L. E. Seeman, to continue thinking about further nuclear use and its relationship to a possible invasion of Japan. As Hull explained, “should we not concentrate on targets that will be of greatest assistance to an invasion rather than industry, morale, psychology, etc.” “Nearer the tactical use”, Seaman agreed and they discussed the tactics that could be used for beach landings. In 1991 articles, Barton Bernstein and Marc Gallicchio used this and other evidence to develop the argument that concepts of tactical nuclear weapons use first came to light at the close of World War II. [69]

Document 88 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1236 – August 13, 1945, Top Secret Ultra

The dropping of two atomic bombs, the tremendous destruction caused by U.S. bombing, and the Soviet declaration of war notwithstanding, important elements of the Japanese Army were unwilling to yield, as was evident from intercepted messages dated 12 and 13 August. Willingness to accept even the “destruction of the Army and Navy” rather than surrender inspired the military coup that unfolded and failed during the night of 14 August.

Document 89 : “The Second  Sacred Judgment”, August 14, 1945

Source :   Hiroshi [Kaian) Shimomura, S husenki [Account of the End of the War]  (Tokyo, Kamakura Bunko, [1948], 148-152 [Translated by Toshihiro Higuchi]

Frightened by the rapid movement of Soviet forces into Manchuria and worried that the army might launch a coup, the peace party set in motion a plan to persuade Hirohito to meet with the cabinet and the “Big Six” to resolve the stalemate over the response to the Allies. Japan was already a day late in responding to the Byrnes Note and Hirohito agreed to move quickly. At 10:50 a.m., he met with the leadership at the bomb shelter in his palace. This account, prepared by Director of Information Shimomura, conveys the drama of the occasion (as well as his interest in shifting the blame for the debacle to the Army). After Suzuki gave the war party--Umeda, Toyoda, and Anami--an opportunity to present their arguments against accepting the Byrnes Note, he asked the emperor to speak. 

  Hirohito asked the leadership to accept the Note, which he believed was “well intentioned” on the matter of the “national polity” (by leaving open a possible role for the Emperor).  Arguing that continuing the war would reduce the nation “to ashes,” his words about “bearing the unbearable” and sadness over wartime losses and suffering prefigured the language that Hirohito would use in his public announcement the next day. According to Bix, “Hirohito's language helped to transform him from a war to a peace leader, from a cold, aloof monarch to a human being who cared for his people” but “what chiefly motivated him … was his desire to save a politically empowered throne with himself on it.” [70]

Hirohito said that he would make a recording of the surrender announcement so that the nation could hear it. That evening army officers tried to seize the palace and find Hirohito’s recording, but the coup failed. Early the next day, General Anami committed suicide. On the morning of August 15, Hirohito broadcast the message to the nation (although he never used the word “surrender”). A few weeks later, on September 2, 1945 Japanese representatives signed surrender documents on the USS  Missouri , in Tokyo harbor. [71]

Document 90 : “Magic” – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 515, August 18, 1945

This summary includes an intercepted account of the destruction of Nagasaki.

Document 91 :Washington Embassy Telegram 5599 to Foreign Office, 14 August 1945, Top Secret [72]

Source: The British National Archives, Records of the Foreign and Commonwealth Office,  FO 800/461

With the Japanese surrender announcement not yet in, President Truman believed that another atomic bombing might become necessary. After a White House meeting on 14 August, British Minister John Balfour reported that Truman had “remarked sadly that he now had no alternative but to order an atomic bomb to be dropped on Tokyo.” This was likely emotional thinking spurred by anxiety and uncertainty. Truman was apparently not considering the fact that Tokyo was already devastated by fire bombing and that an atomic bombing would have killed the Emperor, which would have greatly complicated the process of surrender. Moreover, he may not have known that the third bomb was still in the United States and would not be available for use for nearly another week. [73]  As it turned out, a few hours later, at 4:05 p.m., the White House received the Japanese surrender announcement.

XI. Confronting the Problem of Radiation Poisoning

Document 92 : P.L. Henshaw and R.R. Coveyou to H.J. Curtis and K. Z. Morgan, “Death from Radiation Burns,” 24 August 1945, Confidential

Source: Department of Energy Open-Net

Two scientists at Oak Ridge’s Health Division, Henshaw and Coveyou, saw a United Press report in the Knoxville  News Sentinel  about radiation sickness caused by the bombings. Victims who looked healthy weakened, “for unknown reasons” and many died. Lacking direct knowledge of conditions in Hiroshima and Nagasaki, Henshaw and Coveyou had their own data on the biological effects of radiation and could make educated guesses. After reviewing the impact of various atomic bomb effects--blast, heat, flash radiation (prompt effects from gamma waves), and radiation from radioactive substances--they concluded that “it seems highly plausible that a great many persons were subjected to lethal and sub-lethal dosages of radiation in areas where direct blast effects were possibly non-lethal.” It was “probable,” therefore, that radiation “would produce increments to the death rate and “even more probable” that a “great number of cases of sub-lethal exposures to radiation have been suffered.” [74]

Document 93 : Memorandum of Telephone Conversation Between General Groves and Lt. Col. Rea, Oak Ridge Hospital, 9:00 a.m., August 28, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5b

Despite the reports pouring in from Japan about radiation sickness among the victims of Hiroshima and Nagasaki, General Groves and Dr. Charles Rea, a surgeon who was head of the base hospital at Oak Ridge (and had no specialized knowledge about the biological effects of radiation) dismissed the reports as “propaganda”. Unaware of the findings of Health Division scientists, Groves and Rhea saw the injuries as nothing more than “good thermal burns.” [75]

Documents 94A-B: General Farrell Surveys the Destruction

94A . Cable CAX 51813 from  USS Teton  to Commander in Chief Army Forces Pacific Administration, From Farrell to Groves, September 10, 1945, Secret

94B . Cable CAX 51948 from Commander in Chief Army Forces Pacific Advance Yokohoma Japan to Commander in Chief Army Forces Pacific Administration, September 14, 1945, Secret

Source: RG 77, Tinian Files, April-December 1945, box 17, Envelope B

A month after the attacks Groves’ deputy, General Farrell, traveled to Japan to see for himself the destruction of Hiroshima and Nagasaki. His vivid account shows that senior military officials in the Manhattan Project were no longer dismissive of reports of radiation poisoning. As Farrell observed in his discussion of Hiroshima, “Summaries of Japanese reports previously sent are essentially correct, as to clinical effects from single gamma radiation dose.” Such findings dismayed Groves, who worried that the bomb would fall into a taboo category like chemical weapons, with all the fear and horror surrounding them. Thus, Groves and others would try to suppress findings about radioactive effects, although that was a losing proposition. [76]

XII. Eisenhower and McCloy’s Views on the Bombings and Atomic Weapons

Document 95 : Entry for 4 October 1945, Robert P. Meiklejohn Diary

In this entry written several months later, Meiklejohn shed light on what much later became an element of the controversy over the Hiroshima-Nagasaki bombings: whether any high level civilian or military officials objected to nuclear use. Meiklejohn recounted Harriman’s visit in early October 1945 to the Frankfurt-area residence of General Dwight Eisenhower, who was finishing up his service as Commanding General, U.S. Army, European Theater. It was Meiklejohn’s birthday and during the dinner party, Eisenhower and McCloy had an interesting discussion of atomic weapons, which included comments alluding to scientists’ statements about what appears to be the H-bomb project (a 20 megaton weapon), recollection of the early fear that an atomic detonation could burn up the atmosphere, and the Navy’s reluctance to use its battleships to test atomic weapons. At the beginning of the discussion, Eisenhower made a significant statement: he “mentioned how he had hoped that the war might have ended without our having to use the atomic bomb.” The general implication was that prior to Hiroshima-Nagasaki, he had wanted to avoid using the bomb.

Some may associate this statement with one that Eisenhower later recalled making to Stimson. In his 1948 memoirs (further amplified in his 1963 memoirs), Eisenhower claimed that he had “expressed the hope [to Stimson] that we would never have to use such a thing against an enemy because I disliked seeing the United States take the lead in introducing into war something as horrible and destructive as this new weapon was described to be.” That language may reflect the underlying thinking behind Eisenhower’s statement during the dinner party, but whether Eisenhower used such language when speaking with Stimson has been a matter of controversy. In later years, those who knew both thought it unlikely that the general would have expressed misgivings about using the bomb to a civilian superior. Eisenhower’s son John cast doubts about the memoir statements, although he attested that when the general first learned about the bomb he was downcast.

Stimson’s diary mentions meetings with Eisenhower twice in the weeks before Hiroshima, but without any mention of a dissenting Eisenhower statement (and Stimson’s diaries are quite detailed on atomic matters). The entry from Meiklejohn’s diary does not prove or disprove Eisenhower’s recollection, but it does confirm that he had doubts which he expressed only a few months after the bombings. Whether Eisenhower expressed such reservations prior to Hiroshima will remain a matter of controversy. [77]

Document 96:  President Harry S. Truman, Handwritten Remarks for Gridiron Dinner, circa 15 December 1945 [78]

Source: Harry S. Truman Library,  President's Secretary's Files,  Speech Files, 1945-1953,  copy on U.S. National Archives Web Site

On 15 December, President Truman spoke about the atomic bombings in his speech at the annual dinner of the Gridiron Club, organized by bureau chiefs and other leading figures of print media organizations. Besides Truman, guests included New York Governor Thomas Dewey (Republican presidential candidate in 1944 and 1948), foreign ambassadors, members of the cabinet and the Supreme Court, the military high command, and various senators and representatives. The U.S. Marine Band provided music for the dinner and for the variety show that was performed by members of the press.  [79]

In accordance with the dinner’s rules that “reporters are never present,” Truman’s remarks were off-the record. The president, however, wrote in long-hand a text that that might approximate what he said that evening. Pages 12 through 15 of those notes refer to the atomic bombing of Japan:

“You know the most terrible decision a man ever had to make was made by me at Potsdam. It had nothing to do with Russia or Britain or Germany. It was a decision to loose the most terrible of all destructive forces for the wholesale slaughter of human beings. The Secretary of War, Mr. Stimson, and I weighed that decision most prayerfully. But the President had to decide. It occurred to me that a quarter of a million of the flower of our young manhood was worth a couple of Japanese cities, and I still think that they were and are. But I couldn’t help but think of the necessity of blotting out women and children and non-combatants. We gave them fair warning and asked them to quit. We picked a couple of cities where war work was the principle industry, and dropped bombs. Russia hurried in and the war ended.”

Truman characterized the Potsdam Declaration as a “fair warning,” but it was an ultimatum. Plainly he was troubled by the devastation and suffering caused by the bombings, but he found it justifiable because it saved the lives of U.S. troops. His estimate of 250,000 U.S. soldiers spared far exceeded that made by General Marshall in June 1945, which was in the range of 31,000 (comparable to the Battle of Luzon) [See Document 26]. By citing an inflated casualty figure, the president was giving a trial run for the rationale that would become central to official and semi-official discourse about the bombings during the decades ahead. [80]  

Despite Truman’s claim that he made “the most terrible” decision at Potsdam, he assigned himself more responsibility than the historical record supports. On the basic decision, he had simply concurred with the judgments of Stimson, Groves, and others that the bomb would be used as soon as it was available for military use. As for targeting, however, he had a more significant role. At Potsdam, Stimson raised his objections to targeting Japan’s cultural capital, Kyoto, and Truman supported the secretary’s efforts to drop that city from the target list [See Documents 47 and 48].  [81]

Where he had taken significant responsibility was by making a decision to stop the atomic bombings just before the Japanese surrender, thereby asserting presidential control over nuclear weapons

The editor thanks Barton J. Bernstein, J. Samuel Walker, Gar Alperovitz, David Holloway, and Alex Wellerstein for their advice and assistance, and Tsuyoshi Hasegawa for kindly providing copies of some of the Japanese sources that were translated for this compilation. Hasegawa’s book,  Racing the Enemy: Stalin, Truman, and the Surrender of Japan  (Cambridge, Harvard University Press, 2005), includes invaluable information on Japanese sources. David Clark, an archivist at the Harry S. Truman Library, and James Cross, Manuscripts Archivist at Clemson University Library’s Special Collections, kindly provided material from their collections. The editor also thanks Kyle Hammond and Gregory Graves for research assistance and Toshihiro Higuchi and Hikaru Tajima (who then were graduate students in history at Georgetown University and the University of Tokyo respectively), for translating documents and answering questions on the Japanese sources. The editor thanks Anna Melyakova (National Security Archive) for translating Russian language material.

Read the documents

I. background on the u.s. atomic project   documents 1a-c: report of the uranium committee.

Document 1A

National Archives, Records of the Office of Scientific Research and Development, Record Group 227 (hereinafter RG 227), Bush-Conant papers microfilm collection, Roll 1, Target 2, Folder 1, "S-1 Historical File, Section A (1940-1941)."

Document 1B

See description of document 1A.

Document 1C

Document 2A

RG 227, Bush-Conant papers microfilm collection, Roll 1, Target 2, Folder 1, "S-1 Historical File, Section II (1941-1942)

Document 2B

Bush-Conant papers, S-1 Historical File, Reports to and Conferences with the President (1942-1944)

See description of document 2A.

National Archives, Record Group 77, Records of the Army Corps of Engineers (hereinafter RG 77), Manhattan Engineering District (MED), Minutes of the Military Policy Meeting (5 May 1943), Correspondence (“Top Secret”) of the Manhattan Engineer District, 1942-1946, microfilm publication M1109 (Washington, D.C.: National Archives and Records Administration, 1980), Roll 3, Target 6, Folder 23, “Military Policy Committee, Minutes of Meetings”

Before the Manhattan Project had produced any weapons, senior U.S. government officials had Japanese targets in mind. Besides discussing programmatic matters (e.g., status of gaseous diffusion plants, heavy water production for reactors, and staffing at Las Alamos), the participants agreed that the first use could be Japanese naval forces concentrated at Truk Harbor, an atoll in the Caroline Islands. If there was a misfire the weapon would be difficult for the Japanese to recover, which would not be the case if Tokyo was targeted. Targeting Germany was rejected because the Germans were considered more likely to “secure knowledge” from a defective weapon than the Japanese. That is, the United States could possibly be in danger if the Nazis acquired more knowledge about how to build a bomb. [9]

RG 77, Correspondence ("Top Secret") of the Manhattan Engineer District, 1942-1946, file 25M

This memorandum from General Groves to General Marshall captured how far the Manhattan Project had come in less than two years since Bush’s December 1942 report to President Roosevelt. Groves did not mention this but around the time he wrote this the Manhattan Project had working at its far-flung installations over 125,000 people ; taking into account high labor turnover some 485,000 people worked on the project (1 out of every 250 people in the country at that time). What these people were laboring to construct, directly or indirectly, were two types of weapons—a gun-type weapon using U-235 and an implosion weapon using plutonium (although the possibility of U-235 was also under consideration). As the scientists had learned, a gun-type weapon based on plutonium was “impossible” because that element had an “unexpected property”: spontaneous neutron emissions would cause the weapon to “fizzle.” [10] For both the gun-type and the implosion weapons, a production schedule had been established and both would be available during 1945. The discussion of weapons effects centered on blast damage models; radiation and other effects were overlooked.

RG 77, Harrison-Bundy Files (H-B Files), folder 69 (copy from microfilm)

Documents 6A-D: President Truman Learns the Secret

Document 6A

G 77, Commanding General’s file no. 24, tab D

Soon after he was sworn in as president following President Roosevelt’s death, Harry Truman learned about the top secret Manhattan Project from briefings by  Secretary of War Stimson and Manhattan Project chief General Groves (who went through the “back door” to escape the watchful press). Stimson, who later wrote up the meeting in his diary, also prepared a discussion paper, which raised broader policy issues associated with the imminent possession of “the most terrible weapon ever known in human history.”

In a background report prepared for the meeting, Groves provided a detailed overview of the bomb project from the raw materials to processing nuclear fuel to assembling the weapons to plans for using them, which were starting to crystallize. With respect to the point about assembling the weapons, Groves and Stimson informed Truman that the first gun-type weapon “should be ready about 1 August 1945” while an implosion weapon would also be available that month. “The target is and was always expected to be Japan.”  

These documents have important implications for the perennial debate over whether Truman “inherited assumptions” from the Roosevelt administration that the bomb would be used when available or that he made  the  decision to do so.  Alperovitz and Sherwin have argued that Truman made “a real decision” to use the bomb on Japan by choosing “between various forms of diplomacy and warfare.” In contrast, Bernstein found that Truman “never questioned [the] assumption” that the bomb would and should be used. Norris also noted that “Truman’s ”decision” amounted to a decision not to override previous plans to use the bomb.” [12]

Document 6B

Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress)

See description of document 6A.

Document 6C

Record Group 200, Papers of General Leslie R. Groves, Correspondence 1941-1970, box 3, “F”

Document 6D

RG 77, MED Records, Top Secret Documents, File no. 5g

The force of B-29 nuclear delivery vehicles that was being readied for first nuclear use—the Army Air Force’s 509 th Composite Group—required an operational base in the Western Pacific. In late February 1945, months before atomic bombs were ready for use, the high command selected Tinian, an island in the Northern Marianas Islands, for that base.

Library of Congress, Curtis LeMay Papers, Box B-36

As part of the war with Japan, the Army Air Force waged a campaign to destroy major industrial centers with incendiary bombs. This document is General Curtis LeMay’s report on the firebombing of Tokyo--“the most destructive air raid in history”--which burned down over 16 square miles of the city, killed up to 100,000 civilians (the official figure was 83,793), injured more than 40,000, and made over 1 million homeless. [13] According to the “Foreword,” the purpose of the raid, which dropped 1,665 tons of incendiary bombs, was to destroy industrial and strategic targets “ not to bomb indiscriminately civilian populations.” Air Force planners, however, did not distinguish civilian workers from the industrial and strategic structures that they were trying to destroy.

RG 77, MED Records, Top Secret Documents, File no. 5d (copy from microfilm)

On 27 April, military officers and nuclear scientists met to discuss bombing techniques, criteria for target selection, and overall mission requirements. The discussion of “available targets” included Hiroshima, the “largest untouched target not on the 21 st Bomber Command priority list.” But other targets were under consideration, including Yawata (northern Kyushu), Yokohama, and Tokyo (even though it was practically “rubble.”) The problem was that the Air Force had a policy of “laying waste” to Japan’s cities which created tension with the objective of reserving some urban targets for nuclear destruction. [16]

Document 10

RG 77, MED Records, Top Secret Documents, File no. 5g (copy from microfilm)

As director of Los Alamos Laboratory, Oppenheimer’s priority was producing a deliverable bomb, but not so much the effects of the weapon on the people at the target. In keeping with General Groves’ emphasis on compartmentalization, the Manhattan Project experts on the effects of radiation on human biology were at the MetLab and other offices and had no interaction with the production and targeting units. In this short memorandum to Groves’ deputy, General Farrell, Oppenheimer explained the need for precautions because of the radiological dangers of a nuclear detonation. The initial radiation from the detonation would be fatal within a radius of about 6/10ths of a mile and “injurious” within a radius of a mile. The point was to keep the bombing mission crew safe; concern about radiation effects had no impact on targeting decisions. [17]

Document 11

Scientists and officers held further discussion of bombing mission requirements, including height of detonation, weather, radiation effects (Oppenheimer’s memo), plans for possible mission abort, and the various aspects of target selection, including priority cities (“a large urban area of more than three miles diameter”) and psychological dimension. As for target cities, the committee agreed that the following should be exempt from Army Air Force bombing so they would be available for nuclear targeting: Kyoto, Hiroshima, Yokohama, and Kokura Arsenal. Japan’s cultural capital, Kyoto, would not stay on the list. Pressure from Secretary of War Stimson had already taken Kyoto off the list of targets for incendiary bombings and he would successfully object to the atomic bombing of that city. [18]

Document 12

Document 13

Joseph E. Davies Papers, Library of Congress, box 17, 21 May 1945

Document 14

Harrison-Bundy Files relating to the Development of the Atomic Bomb, 1942-1946, microfilm publication M1108 (Washington, D.C.: National Archives and Records Administration, 1980), File 77: "Interim Committee - International Control."

In what Stimson called the “letter of an honest man,” Oswald C. Brewster sent President Truman a profound analysis of the danger and unfeasibility of a U.S. atomic monopoly. [21] An engineer for the Kellex Corporation, which was involved in the gas diffusion project to enrich uranium, Brewster recognized that the objective was fissile material for a weapon. That goal, he feared, raised terrifying prospects with implications for the “inevitable destruction of our present day civilization.” Once the U.S. had used the bomb in combat other great powers would not tolerate a monopoly by any nation and the sole possessor would be “be the most hated and feared nation on earth.” Even the U.S.’s closest allies would want the bomb because “how could they know where our friendship might be five, ten, or twenty years hence.” Nuclear proliferation and arms races would be certain unless the U.S. worked toward international supervision and inspection of nuclear plants.

Document 15

Document 16

At the end of May General Groves forwarded to Army Chief of Staff Marshall a “Plan of Operations” for the atomic bombings. While that plan has not surfaced, apparently its major features were incorporated in this 29 May 1945 message on the “special functions” of the 509th Composite Group sent from Chief of Staff General Lauris Norstad to General Curtis LeMay, chief of the XXI Bomber Command, headquartered in the Marianas Islands. [21A] The Norstad message reviewed the complex requirements for preparing B-29s and their crew for delivering nuclear weapons.  He detailed the mission of the specially modified B-29s that comprised the  509th Composite Group, the “tactical factors” that applied,  training and rehearsal issues, and the functions of “special personnel” and the Operational Studies Group.  The targets listed—Hiroshima, Kyoto, and Niigato—were those that had been discussed at the Target Committee meeting on 28 May, but Kyoto would be dropped when Secretary Stimson objected (although that would remain a contested matter) and Kokura would eventually be substituted.   As part of the Composite Group’s training to drop “special bombs,” it would practice with facsimiles—the conventionally-armed “Pumpkins.” The 509th Composite Group’s cover story for its secret mission was the preparation for the use of “Pumpkins” in battle.

Document 17

Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 12, S-1

Tacitly dissenting from the Targeting Committee’s recommendations, Army Chief of Staff George Marshall argued for initial nuclear use against a clear-cut military target such as a “large naval installation.” If that did not work, manufacturing areas could be targeted, but only after warning their inhabitants. Marshall noted the “opprobrium which might follow from an ill considered employment of such force.” This document has played a role in arguments developed by Barton J. Bernstein that figures such as Marshall and Stimson were “caught between an older morality that opposed the intentional killing of non-combatants and a newer one that stressed virtually total war.” [22]

Document 18

RG 77, MED Records, H-B files, folder no. 100 (copy from microfilm)

With Secretary of War Stimson presiding, members of the committee heard reports on a variety of Manhattan Project issues, including the stages of development of the atomic project,  problems of secrecy, the possibility of informing the Soviet Union, cooperation with “like-minded” powers, the military impact of the bomb on Japan, and the problem of “undesirable scientists.”  In his comments on a detonation over Japanese targets, Oppenheimer mentioned that the “neutron effect would be dangerous to life for a radius of at least two-thirds of a mile,” but did not mention that the radiation could cause prolonged sickness.

Interested in producing the “greatest psychological effect,” the Committee members agreed that the “most desirable target would be a vital war plant employing a large number of workers and closely surrounded by workers’ houses.”  Bernstein argues that this target choice represented an uneasy endorsement of “terror bombing”-the target was not exclusively military or civilian; nevertheless, worker’s housing would include non-combatant men, women, and children. [23] It is possible that Truman was informed of such discussions and their conclusions, although he clung to a belief that the prospective targets were strictly military.

Document 19

Record Group 165, Records of the War Department General and Special Staffs, American-British-Canadian Top Secret Correspondence, Box 504, “ABC 387 Japan (15 Feb. 45)

George A. Lincoln, chief of the Strategy and Policy Group at U.S. Army’s Operations Department, commented on a memorandum by former President Herbert Hoover that Stimson had passed on for analysis. Hoover proposed a compromise solution with Japan that would allow Tokyo to retain part of its empire in East Asia (including Korea and Japan) as a way to head off Soviet influence in the region. While Lincoln believed that the proposed peace teams were militarily acceptable he doubted that they were workable or that they could check Soviet “expansion” which he saw as an inescapable result of World War II. As to how the war with Japan would end, he saw it as “unpredictable,” but speculated that “it will take Russian entry into the war, combined with a landing, or imminent threat of a landing, on Japan proper by us, to convince them of the hopelessness of their situation.” Lincoln derided Hoover’s casualty estimate of 500,000. J. Samuel Walker has cited this document to make the point that “contrary to revisionist assertions, American policymakers in the summer of 1945 were far from certain that the Soviet invasion of Manchuria would be enough in itself to force a Japanese surrender.” [24]

Document 20

Document 21

Henry Stimson Papers, Sterling Library, Yale University (microfilm at Library of Congress)

Stimson and Truman began this meeting by discussing how they should handle a conflict with French President DeGaulle over the movement by French forces into Italian territory. (Truman finally cut off military aid to France to compel the French to pull back). [25] As evident from the discussion, Stimson strongly disliked de Gaulle whom he regarded as “psychopathic.” The conversation soon turned to the atomic bomb, with some discussion about plans to inform the Soviets but only after a successful test. Both agreed that the possibility of a nuclear “partnership” with Moscow would depend on “quid pro quos”: “the settlement of the Polish, Rumanian, Yugoslavian, and Manchurian problems.”

At the end, Stimson shared his doubts about targeting cities and killing civilians through area bombing because of its impact on the U.S.’s reputation as well as on the problem of finding targets for the atomic bomb. Barton Bernstein has also pointed to this as additional evidence of the influence on Stimson of an “an older morality.” While concerned about the U.S.’s reputation, Stimson did not want the Air Force to bomb Japanese cities so thoroughly that the “new weapon would not have a fair background to show its strength,” a comment that made Truman laugh. The discussion of “area bombing” may have reminded him that Japanese civilians remained at risk from U.S. bombing operations.

Document 22

RG 77, MED Records, H-B files, folder no. 76 (copy from microfilm)

Physicists Leo Szilard and James Franck, a Nobel Prize winner, were on the staff of the “Metallurgical Laboratory” at the University of Chicago, a cover for the Manhattan Project program to produce fuel for the bomb. The outspoken Szilard was not involved in operational work on the bomb and General Groves kept him under surveillance but Met Lab director Arthur Compton found Szilard useful to have around. Concerned with the long-run implications of the bomb, Franck chaired a committee, in which Szilard and Eugene Rabinowitch were major contributors, that produced a report rejecting a surprise attack on Japan and recommended instead a demonstration of the bomb on the “desert or a barren island.” Arguing that a nuclear arms race “will be on in earnest not later than the morning after our first demonstration of the existence of nuclear weapons,” the committee saw international control as the alternative. That possibility would be difficult if the United States made first military use of the weapon. Compton raised doubts about the recommendations but urged Stimson to study the report. Martin Sherwin has argued that the Franck committee shared an important assumption with Truman et al.--that an “atomic attack against Japan would `shock’ the Russians”--but drew entirely different conclusions about the import of such a shock. [26]

Document 23

Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 8, Japan (After December 7/41)

Document 24

Document 25

Document 26

Record Group 218, Records of the Joint Chiefs of Staff, Central Decimal Files, 1942-1945, box 198 334 JCS (2-2-45) Mtg 186th-194th

The record of this meeting has figured in the complex debate over the estimates of casualties stemming from a possible invasion of Japan. While post-war justifications for the bomb suggested that an invasion of Japan could have produced very high levels of casualties (dead, wounded, or missing), from hundreds of thousands to a million, historians have vigorously debated the extent to which the estimates were inflated. [29]

Document 27

Document 28

RG 77, MED, H-B files, folder no. 77 (copy from microfilm)

Document 29

Document 30

RG 107, Office of Assistant Secretary of War Formerly Classified Correspondence of John J. McCloy, 1941-1945, box 38, ASW 387 Japan

Document 31

Document 32

Document 33

Naval Aide to the President Files, box 4, Berlin Conference File, Volume XI - Miscellaneous papers: Japan, Harry S. Truman Presidential Library

On 2 July Stimson presented to President Truman a proposal that he had worked up with colleagues in the War Department, including McCloy, Marshall, and Grew. The proposal has been characterized as “the most comprehensive attempt by any American policymaker to leverage diplomacy” in order to shorten the Pacific War. Stimson had in mind a “carefully timed warning” delivered before the invasion of Japan. Some of the key elements of Stimson’s argument were his assumption that “Japan is susceptible to reason” and that Japanese might be even more inclined to surrender if “we do not exclude a constitutional monarchy under her present dynasty.” The possibility of a Soviet attack would be part of the “threat.” As part of the threat message, Stimson alluded to the “inevitability and completeness of the destruction” which Japan could suffer, but he did not make it clear whether unconditional surrender terms should be clarified before using the atomic bomb. Truman read Stimson’s proposal, which he said was “powerful,” but made no commitments to the details, e.g., the position of the emperor. [32]

Document 34

Record Group 353, Records of Interdepartmental and Intradepartmental Committees, Secretary’s Staff Meetings Minutes, 1944-1947 (copy from microfilm)

Document 35

RG 218, Central Decimal Files, 1943-1945, CCS 381 (6-4-45), Sec. 2 Pt. 5

Document 36

Record Group 59, Decimal Files 1945-1949, 740.0011 PW (PE)/7-1645

Document 37

Henry L. Stimson Papers (MS 465), Sterling Library, Yale University (reel 113) (microfilm at Library of Congress)

Still interested in trying to find ways to “warn Japan into surrender,” this represents an attempt by Stimson before the Potsdam conference, to persuade Truman and Byrnes to agree to issue warnings to Japan prior to the use of the bomb. The warning would draw on the draft State-War proclamation to Japan; presumably, the one criticized by Hull (above) which included language about the emperor. Presumably the clarified warning would be issued prior to the use of the bomb; if the Japanese persisted in fighting then “the full force of our new weapons should be brought to bear” and a “heavier” warning would be issued backed by the “actual entrance of the Russians in the war.” Possibly, as Malloy has argued, Stimson was motivated by concerns about using the bomb against civilians and cities, but his latest proposal would meet resistance at Potsdam from Byrnes and other. [34]

Document 38

IV. The Japanese Search for Soviet Mediation   Documents 39A-B: Magic

Document 39A

National Security Agency Mandatory declassification review release.

Beginning in September 1940, U.S. military intelligence began to decrypt routinely, under the “Purple” code-name, the intercepted cable traffic of the Japanese Foreign Ministry. Collectively the decoded messages were known as “Magic.” How this came about is explained in an internal history of pre-war and World War II Army and Navy code-breaking activities prepared by William F. Friedman , a central figure in the development of U.S. government cryptology during the 20 th century. The National Security Agency kept the ‘Magic” diplomatic and military summaries classified for many years and did not release the entire series for 1942 through August 1945 until the early 1990s. [36]

Document 39B

Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18.

Document 40

RG 165, Army Operations OPD Executive File #17, Item 13 (copy courtesy of J. Samuel Walker)

Document 41

Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18

Document 42

Document 43

Takashi Itoh, ed., Sokichi Takagi: Nikki to Joho [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 916-917 [Translation by Hikaru Tajima]

Document 44

L.D. Riabev, ed., Atomnyi Proekt SSSR (Moscow: izd MFTI, 2002), Volume 1, Part 2, 335-336

This 10 July 1945 letter from NKVD director V. N. Merkulov to Beria is an example of Soviet efforts to collect inside information on the Manhattan Project, although not all the detail was accurate. Merkulov reported that the United States had scheduled the test of a nuclear device for that same day, although the actual test took place 6 days later. According to Merkulov, two fissile materials were being produced: element-49 (plutonium), and U-235; the test device was fueled by plutonium. The Soviet source reported that the weight of the device was 3 tons (which was in the ball park) and forecast an explosive yield of 5 kilotons. That figure was based on underestimates by Manhattan Project scientists: the actual yield of the test device was 20 kilotons.

Document 45

RG 77, MED Records, Top Secret Documents, File 5e (copy from microfilm)

An elated message from Harrison to Stimson reported the success of the Trinity Test of a plutonium implosion weapon. The light from the explosion could been seen “from here [Washington, D.C.] to “high hold” [Stimson’s estate on Long Island—250 miles away]” and it was so loud that Harrison could have heard the “screams” from Washington, D.C. to “my farm” [in Upperville, VA, 50 miles away] [42]

Document 46

RG 77, MED Records, Top Secret Documents, File no. 4 (copy from microfilm)

Document 47

Barton J. Bernstein, “Truman at Potsdam: His Secret Diary,” Foreign Service Journal, July/August 1980, excerpts, used with author’s permission. [44]

Some years after Truman’s death, a hand-written diary that he kept during the Potsdam conference surfaced in his personal papers. For convenience, Barton Bernstein’s rendition is provided here but linked here are the scanned versions of Truman’s handwriting on the National Archives’ website (for 15-30 July).

Document 48

An important question that Stimson discussed with Marshall, at Truman’s request, was whether Soviet entry into the war remained necessary to secure Tokyo’s surrender. Marshall was not sure whether that was so although Stimson privately believed that the atomic bomb would provide enough to force surrender (see entry for July 23). This entry has been cited by all sides of the controversy over whether Truman was trying to keep the Soviets out of the war. [46] During the meeting on August 24, discussed above, Stimson gave his reasons for taking Kyoto off the atomic target list: destroying that city would have caused such “bitterness” that it could have become impossible “to reconcile the Japanese to us in that area rather than to the Russians.” Stimson vainly tried to preserve language in the Potsdam Declaration designed to assure the Japanese about “the continuance of their dynasty” but received Truman’s assurance that such a consideration could be conveyed later through diplomatic channels (see entry for July 24). Hasegawa argues that Truman realized that the Japanese would refuse a demand for unconditional surrender without a proviso on a constitutional monarchy and that “he needed Japan’s refusal to justify the use of the atomic bomb.” [47]

Document 49

Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 10, folder 12, Byrnes, James F.: Potsdam, Minutes, July-August 1945

The degree to which the typed-up version reflects the original is worth investigating. In any event, historians have used information from the diary to support various interpretations. For example, Bernstein cites the entries for 20 and 24 July to argue that “American leaders did not view Soviet entry as a substitute for the bomb” but that the latter “would be so powerful, and the Soviet presence in Manchuria so militarily significant, that there was no need for actual Soviet intervention in the war.” For Brown's diary entry of 3 August 9 1945 historians have developed conflicting interpretations (See discussion of document 57). [48]

Document 50

Document 51

Naval Historical Center, Operational Archives, James Forrestal Diaries

Secretary of the Navy James Forrestal was a regular recipient of “Magic” intercept reports; this substantial entry reviews the dramatic Sato-Togo exchanges covered in the 22 July “Magic” summary (although Forrestal misdated Sato’s cable as “first of July” instead of the 21 st ). In contrast to Alperovitz’s argument that Forrestal tried to modify the terms of unconditional surrender to give the Japanese an out, Frank sees Forrestal’s account of the Sato-Togo exchange as additional evidence that senior U.S. officials understood that Tokyo was not on the “cusp of surrender.” [49]

Document 52

Joseph E. Davies Papers, Library of Congress, Manuscripts Division, box 19, 29 July 1945

VII. Debates among the Japanese – Late July/Early August 1945

Document 53

In the Potsdam Declaration the governments of China, Great Britain, and the United States) demanded the “unconditional surrender of all Japanese armed forces. “The alternative is prompt and utter destruction.” The next day, in response to questions from journalists about the government’s reaction to the ultimatum, Prime Minister Suzuki apparently said that “We can only ignore [ mokusatsu ] it. We will do our utmost to complete the war to the bitter end.” That, Bix argues, represents a “missed opportunity” to end the war and spare the Japanese from continued U.S. aerial attacks. [51] Togo’s private position was more nuanced than Suzuki’s; he told Sato that “we are adopting a policy of careful study.” That Stalin had not signed the declaration (Truman and Churchill did not ask him to) led to questions about the Soviet attitude. Togo asked Sato to try to meet with Soviet Foreign Minister Molotov as soon as possible to “sound out the Russian attitude” on the declaration as well as Japan’s end-the-war initiative. Sato cabled Togo earlier that he saw no point in approaching the Soviets on ending the war until Tokyo had “concrete proposals.” “Any aid from the Soviets has now become extremely doubtful.”

Document 54

Document 55

Document 56

Document 57

Document 58

RG 457, Summaries of Intercepted Japanese Messages (“Magic” Far East Summary, March 20, 1942 – October 2, 1945), box 7, SRS 491-547

Document 59

VIII. The Execution Order   Documents 60A-D: These messages convey the process of creating and transmitting the execution order to bomb Hiroshima. Possibly not wanting to take responsibility for the first use of nuclear weapons, Army Air Force commanders sought formal authorization from Chief of Staff Marshall who was then in Potsdam

Document 60A

RG 77, MED Records, Top Secret Documents, Files no. 5b and 5e (copies from microfilm)

These messages convey the process of creating and transmitting the execution order to bomb Hiroshima.  Possibly not wanting to take responsibility for the first use of nuclear weapons, Army Air Force commanders sought formal authorization from Chief of Staff Marshall who was then in Potsdam. [55] On 22 July Marshall asked Deputy Chief of Staff Thomas Handy to prepare a draft; General Groves wrote one which went to Potsdam for Marshall’s approval. Colonel John Stone, an assistant to commanding General of the Army Air Forces Henry H. “Hap” Arnold, had just returned from Potsdam and updated his boss on the plans as they had developed. On 25 July Marshall informed Handy that Secretary of War Stimson had approved the text; that same day, Handy signed off on a directive which ordered the use of atomic weapons on Japan, with the first weapon assigned to one of four possible targets—Hiroshima, Kokura, Niigata, or Nagasaki. “Additional bombs will be delivery on the [targets] as soon as made ready by the project staff.”

Document 60B

See description of document 60A.

Document 60C

Document 60D

Document 60E

Document 61

RG 77, MED Records, Top Secret Documents, File no. 5

With more information on the Alamogordo test available, Groves provided Marshall with detail on the destructive power of atomic weapons. Barton J. Bernstein has observed that Groves’ recommendation that troops could move into the “immediate explosion area” within a half hour demonstrates the prevalent lack of top-level knowledge of the dangers of nuclear weapons effects. [56] Groves also provided the schedule for the delivery of the weapons: the components of the gun-type bomb to be used on Hiroshima had arrived on Tinian, while the parts of the second weapon to be dropped were leaving San Francisco. By the end of November over ten weapons would be available, presumably in the event the war had continued.

Document 62A

RG 77, Tinian Files, April-December 1945, box 21 (copies courtesy of Barton Bernstein)

Document 62B

See description of document 62A.

Document 62C

Document 63

RG 77, MED Records, Top Secret Documents, File no. 5b (copy from microfilm)

Document 64

Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 68, folder 13, “Transcript/Draft B

Returning from the Potsdam Conference, sailing on the U.S.S. Augusta , Truman learned about the atomic bombing of Hiroshima and announced it twice, first to those in the wardroom (socializing/dining area for commissioned officers), and then to the sailors’ mess. Still unaware of radiation effects, Truman emphasized the explosive yield. Later, he met with Secretary of State Byrnes and they discussed the Manhattan Project’s secrecy and the huge expenditures. Truman, who had been chair of the Senate Special Committee to Investigate the National Defense Program, said that “only on the appeal of Secretary of War Stimson did he refrain and let the War Department continue with the experiment unmolested.”

Document 65

A. Zolotarev, ed., Sovetsko-Iaponskaia Voina 1945 Goda: Istoriia Voenno-Politicheskogo Protivoborstva Dvukh Derzhav v 30–40e Gody (Moscow: Terra, 1997 and 2000), Vol. 7 (1), 340-341.

Document 66

Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 5-9, 1945.

Documents 67A-B: Early High-level Reactions to the Hiroshima Bombing

Document 67A

Gaimusho (Ministry of Foreign Affairs) ed. Shusen Shiroku (The Historical Records of the End of the War), annotated by Jun Eto, volume 4, 57-60 [Excerpts] [Translation by Toshihiro Higuchi]

Excerpts from the Foreign Ministry's compilation about the end of the war show how news of the bombing reached Tokyo as well as how Foreign Minister's Togo initially reacted to reports about Hiroshima. When he learned of the atomic bombing from the Domei News Agency, Togo believed that it was time to give up and advised the cabinet that the atomic attack provided the occasion for Japan to surrender on the basis of the Potsdam Declaration. Togo could not persuade the cabinet, however, and the Army wanted to delay any decisions until it had learned what had happened to Hiroshima. When the Foreign Minister met with the Emperor, Hirohito agreed with him; he declared that the top priority was an early end to the war, although it would be acceptable to seek better surrender terms--probably U.S. acceptance of a figure-head emperor--if it did not interfere with that goal. In light of those instructions, Togo and Prime Minister Suzuki agreed that the Supreme War Council should meet the next day. [59a]

Document 67B

Takashi Itoh, ed., Sokichi Takagi: Nikki to Joho [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 923-924 [Translation by Hikaru Tajima]

Document 68

Document 69

Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 5-9, 1945

Document 70

W.A. Harriman Papers, Library of Congress, box 211, Robert Pickens Meiklejohn World War II Diary At London and Moscow March 10, 1941-February 14, 1946, Volume II (Privately printed, 1980 [Printed from hand-written originals]) (Reproduced with permission)

Document 71

Documents 72A-C: The Attack on Nagasaki

Document 72A

RG 77, Tinian Files, April-December 1945, box 20, Envelope G Tinian Files, Top Secret

Document 72B

See description of document 72A.

Document 72C

Document 73A

Library of Congress, J. Robert Oppenheimer Papers, box 60, Ramsey, Norman

Document 73B

See description of document 73A.

Document 74

Document 75

Zenshiro Hoshina, Daitoa Senso Hishi: Hoshina Zenshiro Kaiso-roku [Secret History of the Greater East Asia War: Memoir of Zenshiro Hoshina] (Tokyo, Japan: Hara-Shobo, 1975), excerpts from Section 5, “The Emperor made go-seidan [= the sacred decision] – the decision to terminate the war,” 139-149 [translation by Hikaru Tajima]

Zenshiro Hoshina, a senior naval official, attended the conference and prepared a detailed account. With Prime Minister Suzuki presiding, each of the ministers had a chance to state their views directly to Hirohito. While Army Minister Anami tacitly threatened a coup (“civil war”), the emperor accepted the majority view that the reply to the Potsdam declaration should include only one condition not the four urged by “Big Six.” Nevertheless, the condition that Hirohito accepted was not the one that foreign minister Togo had brought to the conference. What was at stake was the definition of the kokutai (national policy). Togo’s proposal would have been generally consistent with a constitutional monarchy because it defined the kokutai narrowly as the emperor and the imperial household. What Hirohito accepted, however, was a proposal by the extreme nationalist Kiichiro Hiranuma which drew upon prevailing understandings of the kokutai : the “mythical notion” that the emperor was a living god. “This was the affirmation of the emperor’s theocratic powers, unencumbered by any law, based on Shinto gods in antiquity, and totally incompatible with a constitutional monarchy.” Thus, the Japanese response to the Potsdam declaration opposed “any demand which prejudices the prerogatives of his Majesty as a sovereign ruler.” This proved to be unacceptable to the Truman administration. [63]

Document 76

Document 77A

The first Japanese surrender offer was intercepted shortly before Tokyo broadcast it. This issue of the diplomatic summary also includes Togo’s account of his notification of the Soviet declaration of war, reports of Soviet military operations in the Far East, and intercepts of French diplomatic traffic.

Document 77B

A full translation of the surrender offer was circulated separately. The translations differ but they convey the sticking point that prevented U.S. acceptance: Tokyo’s condition that the allies not make any “demand which prejudices the prerogatives of His Majesty as a sovereign ruler.”

Document 78

Papers of Henry A. Wallace, Special Collections Department, University of Iowa Libraries, Iowa City, Iowa (copy courtesy of Special Collections Department)

Note: The second page of the diary entry includes a newspaper clipping of the Associated Press’s transmission of the Byrnes note. Unfortunately, AP would not authorize the Archive to reproduce this item without payment. Therefore, we are publishing an excised version of the entry, with a link to the Byrnes note .

Document 79

Document 80

Stimson’s account of the events of 10 August focused on the debate over the reply to the Japanese note, especially the question of the Emperor’s status. The U.S. reply , drafted during the course of the day, did not explicitly reject the note but suggested that any notion about the “prerogatives” of the Emperor would be superceded by the concept that all Japanese would be “Subject to the Supreme Commander of the Allied Powers.” The language was ambiguous enough to enable Japanese readers, upon Hirohito’s urging, to believe that they could decide for themselves the Emperor’s future role. Stimson accepted the language believing that a speedy reply to the Japanese would allow the United States to “get the homeland into our hands before the Russians could put in any substantial claim to occupy and help rule it.” If the note had included specific provision for a constitutional monarchy, Hasegawa argues, it would have “taken the wind out of the sails” of the military faction and Japan might have surrendered several days earlier, on August 11 or 12 instead of August 14. [65]

Document 81

Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter Brown Papers, box 68, folder 13, “Transcript/Draft B

Brown recounted Byrnes’ debriefing of the 10 August White House meeting on the Japanese peace offer, an account which differed somewhat from that in the Stimson diary. According to what Byrnes told Brown, Truman, Stimson, and Leahy favored accepting the Japanese note, but Byrnes objected that the United States should “go [no] further than we were willing to go at Potsdam.” Stimson’s account of the meeting noted Byrnes’ concerns (“troubled and anxious”) about the Japanese note and implied that he (Stimson) favored accepting it, but did not picture the debate as starkly as Browns's did.

Document 82

George C. Marshall Papers, George C. Marshall Library, Lexington, VA (copy courtesy of Barton J. Bernstein)

Groves informed General Marshall that he was making plans for the use of a third atomic weapon sometime after 17 August, depending on the weather. With Truman having ordered a halt to the atomic bombings [See document 78], Marshall wrote on Grove's memo that the bomb was “not to be released over Japan without express authority from the President.”

Document 83

Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 10-12, 1945

Document 84

Takashi Itoh, ed., Sokichi Takagi: Nikki to Joho [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 926-927 [Translation by Hikaru Tajima]

Document 85

National Archives, RG 165, Army Operations OPD, Executive Files 1940-1945, box 12, Exec #2

Document 86

Gaimusho [Ministry of Foreign Affairs], ed., Shusen Shiroku [Historical Record of the End of the War] (Tokyo: Hokuyosha, 1977-1978), vol. 5, 27-35 [Translated by Toshihiro Higuchi]

The Byrnes Note did not break the stalemate at the cabinet level. An account of the cabinet debates on August 13 prepared by Information Minister Toshiro Shimamura showed the same divisions as before; Anami and a few other ministers continued to argue that the Allies threatened the kokutai and that setting the four conditions (no occupation, etc.) did not mean that the war would continue. Nevertheless, Anami argued, “We are still left with some power to fight.” Suzuki, who was working quietly with the peace party, declared that the Allied terms were acceptable because they gave a “dim hope in the dark” of preserving the emperor. At the end of the meeting, he announced that he would report to Hirohito and ask him to make another “Sacred Judgment”. Meanwhile, junior Army officers plotted a coup to thwart the plans for surrender. [68]

Document 87

George C. Marshall Library, Lexington, VA, George C. Marshall Papers (copy courtesy of Barton J. Bernstein)

Document 88

Document 89

Hiroshi [Kaian) Shimomura, Shusenki [Account of the End of the War] (Tokyo, Kamakura Bunko, [1948], 148-152 [Translated by Toshihiro Higuchi]

Frightened by the rapid movement of Soviet forces into Manchuria and worried that the army might launch a coup, the peace party set in motion a plan to persuade Hirohito to meet with the cabinet and the “Big Six” to resolve the stalemate over the response to the Allies. Japan was already a day late in responding to the Byrnes Note and Hirohito agreed to move quickly. At 10:50 a.m., he met with the leadership at the bomb shelter in his palace. This account, prepared by Director of Information Shimomura, conveys the drama of the occasion (as well as his interest in shifting the blame for the debacle to the Army). After Suzuki gave the war party--Umeda, Toyoda, and Anami--an opportunity to present their arguments against accepting the Byrnes Note, he asked the emperor to speak.

Hirohito asked the leadership to accept the Note, which he believed was “well intentioned” on the matter of the “national polity” (by leaving open a possible role for the Emperor). Arguing that continuing the war would reduce the nation “to ashes,” his words about “bearing the unbearable” and sadness over wartime losses and suffering prefigured the language that Hirohito would use in his public announcement the next day. According to Bix, “Hirohito's language helped to transform him from a war to a peace leader, from a cold, aloof monarch to a human being who cared for his people” but “what chiefly motivated him … was his desire to save a politically empowered throne with himself on it.” [70]

Hirohito said that he would make a recording of the surrender announcement so that the nation could hear it. That evening army officers tried to seize the palace and find Hirohito’s recording, but the coup failed. Early the next day, General Anami committed suicide. On the morning of August 15, Hirohito broadcast the message to the nation (although he never used the word “surrender”). A few weeks later, on September 2, 1945 Japanese representatives signed surrender documents on the USS Missouri , in Tokyo harbor. [71]

Document 90

Document 91

The British National Archives, Records of the Foreign and Commonwealth Office, FO 800/461

With the Japanese surrender announcement not yet in, President Truman believed that another atomic bombing might become necessary. After a White House meeting on 14 August, British Minister John Balfour reported that Truman had “remarked sadly that he now had no alternative but to order an atomic bomb to be dropped on Tokyo.” This was likely emotional thinking spurred by anxiety and uncertainty. Truman was apparently not considering the fact that Tokyo was already devastated by fire bombing and that an atomic bombing would have killed the Emperor, which would have greatly complicated the process of surrender. Moreover, he may not have known that the third bomb was still in the United States and would not be available for use for nearly another week. [73] As it turned out, a few hours later, at 4:05 p.m., the White House received the Japanese surrender announcement.

Document 92

Department of Energy Open-Net

Two scientists at Oak Ridge’s Health Division, Henshaw and Coveyou, saw a United Press report in the Knoxville News Sentinel about radiation sickness caused by the bombings. Victims who looked healthy weakened, “for unknown reasons” and many died. Lacking direct knowledge of conditions in Hiroshima and Nagasaki, Henshaw and Coveyou had their own data on the biological effects of radiation and could make educated guesses. After reviewing the impact of various atomic bomb effects--blast, heat, flash radiation (prompt effects from gamma and neutron radiation), and radiation from radioactive substances--they concluded that “it seems highly plausible that a great many persons were subjected to lethal and sub-lethal dosages of radiation in areas where direct blast effects were possibly non-lethal.” It was “probable,” therefore, that radiation “would produce increments to the death rate and “even more probable” that a “great number of cases of sub-lethal exposures to radiation have been suffered.” [74]

Document 93

RG 77, MED Records, Top Secret Documents, File no. 5b

Document 94A

RG 77, Tinian Files, April-December 1945, box 17, Envelope B

See description of document 94B

Document 94B

XII. Eisenhower and McCloy’s Views on the Bombings and Atomic Weapons

Document 95

Document 96

Harry S. Truman Library, President's Secretary's Files, Speech Files, 1945-1953, copy on U.S. National Archives Web Site

On 15 December, President Truman spoke about the atomic bombings in his speech at the annual dinner of the Gridiron Club, organized by bureau chiefs and other leading figures of print media organizations. Besides Truman, guests included New York Governor Thomas Dewey (Republican presidential candidate in 1944 and 1948), foreign ambassadors, members of the cabinet and the Supreme Court, the military high command, and various senators and representatives. The U.S. Marine Band provided music for the dinner and for the variety show that was performed by members of the press. [79]

Truman characterized the Potsdam Declaration as a “fair warning,” but it was an ultimatum. Plainly he was troubled by the devastation and suffering caused by the bombings, but he found it justifiable because it saved the lives of U.S. troops. His estimate of 250,000 U.S. soldiers spared far exceeded that made by General Marshall in June 1945, which was in the range of 31,000 (comparable to the Battle of Luzon) [See Document 26]. By citing an inflated casualty figure, the president was giving a trial run for the rationale that would become central to official and semi-official discourse about the bombings during the decades ahead. [80]

Despite Truman’s claim that he made “the most terrible” decision at Potsdam, he assigned himself more responsibility than the historical record supports. On the basic decision, he had simply concurred with the judgments of Stimson, Groves, and others that the bomb would be used as soon as it was available for military use. As for targeting, however, he had a more significant role. At Potsdam, Stimson raised his objections to targeting Japan’s cultural capital, Kyoto, and Truman supported the secretary’s efforts to drop that city from the target list [See Documents 47 and 48]. [81]

[1] . The World Wide Web includes significant documentary resources on these events. The Truman Library has published a helpful collection of archival documents , some of which are included in the present collection. A collection of transcribed documents is Gene Dannen’s “ Atomic Bomb: Decision .” For a print collection of documents, see Dennis Merrill ed.,  Documentary History of the Truman Presidency: Volume I: The Decision to Drop the Atomic Bomb on Japan  (University Publications of America, 1995). A more recent collection of documents, along with a bibliography, narrative, and chronology, is Michael Kort’s  The Columbia Guide to Hiroshima and the Bomb  (New York: Columbia University Press, 2007). An important  on-line collection focuses on the air-raids of Japanese cities and bases, providing valuable context for the atomic attacks.

[2] . For the early criticisms and their impact on Stimson and other former officials, see Barton J. Bernstein, “Seizing the Contested Terrain of Early Nuclear History: Stimson, Conant, and Their Allies Explain the Decision to Use the Atomic Bomb,”  Diplomatic History  17 (1993): 35-72, and James Hershberg,  James B. Conant: Harvard to Hiroshima and the Making of the Nuclear Age  (Stanford, Stanford University Press, 1995), 291-301.

For Stimson’s article, see “The Decision to Use the Atomic Bomb,”  Harper’s  194 (February 1947): 97-107. Social critic Dwight MacDonald published trenchant criticisms immediately after Hiroshima-Nagasaki; see  Politics Past: Essays in Political Criticism  (New York: Viking, 1972), 169-180.

[3] . The proposed script for the Smithsonian exhibition can be seen at Philipe Nobile,

Judgment at the Smithsonian  (New York: Matthews and Company, 1995), pp. 1-127. For reviews of the controversy, see Barton J. Bernstein, “The Struggle Over History: Defining the Hiroshima Narrative,” ibid., 128-256, and Charles T. O’Reilly and William A. Rooney,  The Enola Gay and The Smithsonian  (Jefferson, NC: McFarland and Company, 2005).

[4] . For the extensive literature, see the references in J. Samuel Walker , Prompt and Utter Destruction: Truman and the Use of Atomic Bombs against Japan,  Third Edition (Chapel Hill: University of North Carolina Press, 2016) at 131-136, as well as Walker’s, “Recent Literature on Truman’s Atomic Bomb Decision: A Search for Middle Ground,”  Diplomatic History  29 (April 2005): 311-334. For more recent contributions, see Sean Malloy,  Atomic Tragedy: Henry L. Stimson and the Decision to Use the Bomb Against Japan  (Ithaca: Cornell University Press, 2008), Andrew Rotter,  Hiroshima: The World's Bomb  (New York: Oxford, 2008), Campbell Craig and Sergey Radchenko,  The Atomic Bomb and the Origins of the Cold War  (New Haven, Yale University Press, 2008), Wilson D. Miscamble,  The Most Controversial Decision: Truman, the Atomic Bombs, and the Defeat of Japan  (New York: Cambridge University Press, 2011). Also important to take into account is John Dower’s extensive discussion of Hiroshima/Nagasaki in context of the U.S. fire-bombings of Japanese cities in  Cultures of War: Pearl Harbor/Hiroshima/9-11/Iraq  (New York, W. Norton, 2010), 163-285.

[5] . The editor particularly benefited from the source material cited in the following works: Robert S. Norris,  Racing for the Bomb: General Leslie S. Groves, The Manhattan Project’s Indispensable Man  (South Royalton, VT: Steerforth Press, 2002); Gar Alperovitz,  The Decision to Use the Bomb and the Architecture of an American Myth  (New York: Alfred E. Knopf, 1995); Richard B. Frank , Downfall: The End of the Imperial Japanese Empire  (New York: Random House, 1999), Martin Sherwin,  A World Destroyed: Hiroshima and the Origins of the Arm Race  (New York, Vintage Books, 1987), and as already mentioned, Hasegawa’s  Racing the Enemy: Stalin, Truman, and the Surrender of Japan  (Cambridge, Harvard University Press, 2005 ).  Barton J. Bernstein’s numerous articles in scholarly publications (many of them are listed in Walker’s assessment of the literature) constitute an invaluable guide to primary sources. An article that Bernstein published in 1995, “The Atomic Bombings Reconsidered,”  Foreign Affairs  74 (1995), 135-152, nicely summarizes his thinking on the key issues.   Noteworthy publications since 2015 include Michael D. Gordin and G. John Ikenberry, eds., The Age of Hiroshim a (Princeton: Princeton University Press, 2019); Sheldon Garon, “On the Transnational Destruction of Cities: What Japan and the United States Learned from the Bombing of Britain and Germany in the Second World War,” Past and Present 247 (2020): 235-271; Katherine E. McKinney, Scott Sagan, and Allen S. Weiner, “Why the Atomic Bombing of Hiroshima Would Be Illegal Today,” The Bulletin of the Atomic Scientist s 76 (2020); Gregg Mitchell, The Beginning or the End: How Hollywood and America Learned  to Stop Worrying and Love the Bomb (New York: The New Press, 2020); Steve Olson, The Apocalypse Factory: Plutonium and the Making of the Atomic Age (New York: W.W. Norton, 2020); Neil J. Sullivan, The Prometheus Bomb: The Manhattan Project and Government in the Dark  (Lincoln, NE: University of Nebraska Press/Potomac Books, 2016); Alex Wellerstein; Restricted Data: The History of Nuclear Secrecy in the United States,  (Chicago: University of Chicago Press, forthcoming, 2020), a memoir by a Hiroshima survivor, Taniguchi Sumitero, The Atomic  Bomb on My Back: A Life Story of Survival and Activism (Montpelier, VT: Rootstock Publishing, 2020), and a collection of interviews, Cynthia C. Kelly, ed., The Manhattan Project: The Birth of the Atomic Bomb in the Words of Its Creators, Eyewitnesses, and Historians (Black Dog & Leventhal, 2020).

[6] . Malloy (2008), 49-50. For more on the Uranium Committee, the decision to establish the S-1 Committee, and the overall context, see James G. Hershberg , James B. Conant: Harvard to Hiroshima and the Making of the Nuclear Age  (Stanford, Stanford University Press, 1995), 140-154.

[7] . Sean Malloy, “`A Very Pleasant Way to Die’: Radiation Effects and the Decision to Use the Atomic Bomb against Japan,”  Diplomatic History  36 (2012), especially 523. For an important study of how contemporary officials and scientists looked at the atomic bomb prior to first use in Japan, see Michael D. Gordin,  Five Days in August: How World War II Became a Nuclear War  (Princeton: Princeton University Press, 2007).

[8] . Norris, 169.

[9] . Malloy (2008), 57-58.

[10] . See also Norris, 362.

[11] . For discussion of the importance of this memorandum, see Sherwin, 126-127, and Hershberg , James B. Conant , 203-207.

[12] . Alperovitz, 662; Bernstein (1995), 139; Norris, 377.

[13] . Quotation and statistics from Thomas R. Searle, “`It Made a Lot of Sense to Kill Skilled Workers’: The Firebombing of Tokyo in March 1945,  The Journal of Military History  55 (2002):103. More statistics and a detailed account of the raid is in Ronald Schaffer,  Wings of Judgment: American Bombing in World War II  (New York: Oxford University Press, 1985), 130-137.

[14] . Searle, “`It Made a Lot of Sense to Kill Skilled Workers,’” 118. For detailed background on the Army Air Force’s incendiary bombing planning, see Schaffer (1985) 107-127. On Stimson, see Schaffer (1985), 179-180 and Malloy (2008), 54. For a useful discussion of the firebombing of Tokyo and the atomic bombings, see Alex Wellerstein, “Tokyo vs. Hiroshima,”  Restricted Data: The Nuclear Secrecy Blog ,  22 September 2014

[15] . See for example, Bernstein (1995), 140-141.

[16] . For useful discussion of this meeting and the other Target Committee meetings, see Norris, 382-386.

[17] . Malloy, “A Very Pleasant Way to Die,” 531-534.

[18] . Schaffer,  Wings of Judgment , 143-146.

[19] . Alperovitz argues that the possibility of atomic diplomacy was central to the thinking of Truman and his advisers, while Bernstein, who argues that Truman’s primary objective was to end the war quickly, suggests that the ability to “cow other nations, notably the Soviet Union” was a “bonus” effect. See Bernstein (1995), 142.

[20] . Alperovitz, 147; Robert James Maddox,  Weapons for Victory: The Hiroshima Decision Fifty Years Later  (Columbia: University of Missouri Press, 1995), 52; Gabiel Kolko,  The Politics of War: The World and United States Foreign Policy, 1943-1945  (New York: Pantheon Books, 1990), 421-422. As Alperovitz notes, the Davies papers include variant diary entries and it is difficult to know which are the most accurate.

[21] . Malloy (2008), 112

[21A] . Vincent Jones, Manhattan: The Army and the Atomic Bomb (Washington, D.C.: U.S. Army Center of Military History, 1985), 529.

[22] . Bernstein (1995), 146. See also Barton J. Bernstein, “Looking Back: Gen. Marshall and the Atomic Bombing of Japanese Cities,” Arms Control Today , November 2015.

[23] . Bernstein (1995), 144. See also Malloy (2008), at 116-117, including the argument that 1) Stimson was deceiving himself by accepting the notion that a “vital war plant …surrounded by workers’ houses” was a legitimate military target, and 2) that Groves was misleading Stimson by withholding the Target Committee’s conclusions that the target would be a city center.

[24] . Walker (2005), 320.

[25] . Frank Costigliola,  France and the United States: The Cold Alliance Since World War II  (New York, Twayne, 1992), 38-39.

[26] . Barton J. Bernstein, Introduction to Helen S. Hawkins et al. editors,  Toward a Livable World: Leo Szilard and the Crusade for Nuclear Arms Control  (Cambridge: MIT Press, 1987), xxx-xxv; Sherwin, 210-215.

[27] . Herbert P. Bix,  Hirohito and the Making of Modern Japan  (New York: HarperCollins Publishers, 2000), 523.

[28] . Walker (2005), 319-320.

[29] . For a review of the debate on casualty estimates, see Walker (2005), 315, 317-318, 321, 323, and 324-325.

[30] . Hasegawa, 105; Alperovitz, 67-72; Forrest Pogue,  George C. Marshall: Statesman, 1945-1959  (New York: Viking, 1987), 18. Pogue only cites the JCS transcript of the meeting; presumably, an interview with a participant was the source of the McCloy quote.

[31] . Alperovitz, 226; Bernstein, “Understanding the Atomic Bomb and the Japanese Surrender,”  Diplomatic History  19 (1995), 237, note 22.

[32] . Malloy (2008), 123-124.

[33] . Alperovitz, 242, 245; Frank, 219.

[34] . Malloy (2008), 125-127.

[35] . Bernstein, introduction,  Toward a Livable World , xxxvii-xxxviii.

[36] . “Magic” summaries for post-August 1945 remain classified at the National Security Agency. Information from the late John Taylor, National Archives. For background on Magic and the “Purple” code, see John Prados,  Combined Fleet Decoded: The Secret History of American Intelligence and the Japanese Navy in World War II (  New York: Random House, 1995), 161-172 and David Kahn,  The Codebreakers: The Story of Secret Writing  (New York: Scribner, 1996), 1-67.

[37] . Alperovitz, 232-238.

[38] . Maddox, 83-84; Hasegawa, 126-128. See also Walker (2005), 316-317.

[39] . Hasegawa, 28, 121-122.

[40] . Peter Grose,  Gentleman Spy: The Life of Allen Dulles  (Boston: Houghton Mifflin, 1994), 170-174, 248-249.

[41] . David Holloway, “Barbarossa and the Bomb: Two Cases of Soviet Intelligence in World War II,” in Jonathan Haslam and Karina Urbach, eds.,  Secret Intelligence in the European States System, 1918-1989  (Stanford: Stanford University Press, 2014), 63-64. For the inception of the Soviet nuclear program and the role of espionage in facilitating it, see Holloway,  Stalin and the Bomb  (New Haven, Yale University Press, 1994).

[42] . For the distances, see Norris, 407.

[43] . For on-line resources on the first atomic test .

[44] . Bernstein’s detailed commentary on Truman’s diary has not been reproduced here except for the opening pages where he provides context and background.

[45] . Frank, 258; Bernstein (1995), 147; Walker (2005), 322. See also Alex Wellerstein’s “ The Kyoto Misconception ”

[46] . Maddox, 102; Alperovitz, 269-270; Hasegawa, 152-153.

[47] . Hasegawa, 292.

[48] . Bernstein, “Understanding the Atomic Bomb and the Japanese Surrender,”  Diplomatic History  19 (1995), 146-147; Alperovitz, 415; Frank, 246.

[49] . Alperovitz, 392; Frank, 148.

[50] . Alperovitz, 281-282. For Davies at Potsdam, see Elizabeth Kimball MacLean,  Joseph E. Davies: Envoy to the Soviets  (Westport, CT: Praeger, 1992), 151-166

[51] . Hasegawa, 168; Bix, 518.

[52] . Bix, 490, 521.

[53] . Alperovitz, 415; Frank, 246.

[54] . Frank, 273-274; Bernstein, “The Alarming Japanese Buildup on Southern Kyushu, Growing U.S. Fears and Counterfactual Analysis: Would the Planned November 1945 Invasion of Southern Kyushu Have Occurred?”  Pacific Historical Review  68 (1999): 561-609.

[55] . Maddox, 105.

[56] . Barton J. Bernstein, "'Reconsidering the 'Atomic General': Leslie R. Groves,"  The Journal of Military History  67 (July 2003): 883-920. See also Malloy, “A Very Pleasant Way to Die,” 539-540.

[57] . For casualty figures and the experience of people on the ground, see Frank, 264-268 and 285-286, among many other sources. Drawing on contemporary documents and journals, Masuji Ibuse’s novel  Black Rain  (Tokyo, Kodansha, 1982) provides an unforgettable account of the bombing of Hiroshima and its aftermath. For early U.S. planning to detonate the weapon at a height designed to maximize destruction from mass fires and other effects, see Alex Wellerstein, “ The Height of the Bomb .”

[58] . Sadao Asada, “The Shock of the Atomic Bomb and Japan’s Decision to Surrender: A Reconsideration,”  Pacific Historical Review  67 (1998): 101-148; Bix, 523; Frank, 348; Hasegawa, 298. Bix appears to have moved toward a position close to Hasegawa’s; see Bix, “Japan's Surrender Decision and the Monarchy: Staying the Course in an Unwinnable War,”  Japan Focus  . For emphasis on the “shock” of the atomic bomb, see also Lawrence Freedman and Saki Dockrill, “Hiroshima: A Strategy of Shock,” in Saki Dockrill, ed.,  From Pearl Harbor to Hiroshima : the Second World War in Asia and the Pacific, 1941-1945  (New York, St. Martin’s Press, 1994), 191-214. For more on the debate over Japan’s surrender, see Hasegawa’s important edited book,  The End of the Pacific War: A Reappraisal  (Stanford: Stanford University Press, 2007), with major contributions by Hasegawa, Holloway, Bernstein, and Hatano.

[59] . Melvyn P. Leffler, “Adherence to Agreements: Yalta and the Experiences of the Early Cold War,”  International Security  11 (1986): 107; Holloway, “Barbarossa and the Bomb,” 65.

[59a] . For more on these developments, see Asada, "The Shock of the Atomic Bomb and Japan's Decision to Surrender: A Reconsideration," 486-488.

[60] . Hasegawa, 191-192.

[61] . Frank, 286-287; Sherwin, 233-237; Bernstein (1995), 150; Maddox, 148.

[62] . The Supreme War Council comprised the prime minister, foreign minister, army and navy ministers, and army and navy chiefs of staff; see Hasegawa, 72 .

[63] . For the maneuverings on August 9 and the role of the  kokutai , see Hasegawa, 3-4, 205-214

[64] . For Truman’s recognition of mass civilian casualties, see also his  letter to Senator Richard Russell, 9 August 1945.

[65] . Hasegawa, 295.

[66] . For “tug of war,” see Hasegawa, 226-227.

[67] . Hasegawa, 228-229, 232.

[68] . Hasegawa, 235-238.

[69] . Barton J. Bernstein, “Eclipsed by Hiroshima and Nagasaki: Early Thinking about Tactical Nuclear Weapons,”  International Security  15 (Spring 1991): 149-173; Marc Gallicchio, “After Nagasaki: General Marshall’s Plans for Tactical Nuclear Weapons in Japan,”  Prologue  23 (Winter 1991): 396-404. Letters from Robert Messer and Gar Alperovitz, with Bernstein’s response, provide insight into some of the interpretative issues. “Correspondence,”  International Security  16 (Winter 1991/1992): 214-221.

[70] . Bix, “Japan's Surrender Decision and the Monarchy: Staying the Course in an Unwinnable War,”  Japan Focus .

[71] . For Hirohito' surrender speech--the actual broadcast and a translation--see  Japan Times , August 2015.

[72] . Cited by Barton J. Bernstein, “Eclipsed by Hiroshima and Nagasaki: Early Thinking About Tactical Nuclear Weapons,”  International Security  15 (1991) at page 167. Thanks to Alex Wellerstein for the suggestion and the archival link.

[73] . For further consideration of Tokyo and more likely targets at the time, see Alex Wellerstein, “Neglected Niigata,”  Restricted Data: The Nuclear Secrecy Blog, 9 October 2015.

[74] . See Malloy, “A Very Pleasant Way to Die,” 541-542.

[75] . For Groves and the problem of radiation sickness, see Norris, 339-441, Bernstein, “Reconsidering the ‘Atomic General’: Leslie R. Groves,”  Journal of Military History  67 (2003), 907-908, and Malloy, “A Very Pleasant Way to Die,” 513-518 and 539-542

[76] . See Janet Farrell Brodie, “Radiation Secrecy and Censorship after Hiroshima and Nagasaki,”  The Journal of Social History  48 (2015): 842-864.

[77] . For Eisenhower’s statements, see  Crusade in Europe  (Garden City: Doubleday, 1948), 443, and  Mandate for Change  (Garden City: Doubleday, 1963), 312-313. Barton J. Bernstein’s 1987 article, “Ike and Hiroshima: Did He Oppose It?”  The Journal of Strategic Studies  10 (1987): 377-389, makes a case against relying on Eisenhower’s memoirs and points to relevant circumstantial evidence. For a slightly different perspective, see Malloy (2007), 138

[78] . Cited in Barton J. Bernstein, “Truman and the A-Bomb: Targeting Noncombatants, Using the Bomb, and His Defending the "Decision,”  The Journal of Military History  62 (1998), at page 559. Thanks to Alex Wellerstein for the suggestion and the archival link.

[79] . “Truman Plays Part of Himself in Skit at Gridiron Dinner,” and “List of Members and Guests at the Gridiron Show,”  The Washington Post , 16 December 1945.

[80] . For varied casualty figures cited by Truman and others after the war, see Walker,  Prompt and Utter Destruction: Truman and the Use of Atomic Bombs Against Japan , 101-102.

[81] . See also ibid., 59.

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On the History and Technology of the Atomic Bomb. The Commitment of the Scientists

• First Online: 01 January 2015

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• Vincenzo Cioci 3 , 4  

Part of the book series: History of Mechanism and Machine Science ((HMMS,volume 27))

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The development of the atomic bomb in the first half of the twentieth century marked a turning point in the history of nuclear science because it revealed the close relationships that exist among science, technology and society. In this paper the main discoveries that led to the scientific and technological development of the atomic bomb are presented together with the commitment of scientists who tried to avoid possible harmful uses of the results of their researches.

In this work a deep examination of the writings of some of these scientists is introduced, some of which are still unpublished, although already quoted by several authors, with the purpose to highlight the relevance of their position against the bomb to the present day. In this sense the content of the paper may appear as a novelty within the history of science and technology; even if it cannot be a unique story.

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After Crossroads: The Fate of the Atomic Bomb Target Fleet

Revisiting the Frisch–Peierls Memorandum

Impact on Science and Technology

1 Rutherford won the Nobel Prize for Chemistry in 1908 “for his investigations into the disintegration of the elements and the chemistry of radioactive substances”, although the chemist of the team was Soddy. He gained due recognition only with the Nobel Prize in 1921 “for his contributions to our knowledge of the chemistry of radioactive substances and his investigations into the origin and nature of isotopes”. In 1913, in fact, he had found that certain elements exist in two or more forms with different atomic weights but they are chemically indistinguishable. Between 1911 and 1913, he had also formulated the Law of radioactive displacement, which refers to the fact that the emission of an α particle by an element moves it back two places in the periodic table, while the emission of a β particle situates it in one position forward. His naming to the Royal Swedish Academy of Sciences was proposed by Rutherford (and supported by Thomson), as if to repay the debt contract with Soddy on the occasion of the Nobel Prize in 1908.

In March 1903, Pierre Curie (1859–1906) and Albert Laborde (1878–1968) had measured the heat developed in a Bunsen ice calorimeter from a known amount of radio in a defined time. They found enormous values of the order of 100 calories per hour for a single gram of radium (Curie and Laborde 1903 ). These authors, however, did not consider it possible that this heat was developed at the expense of the internal energy of the radium but they thought that it came from a source outside the atom, of unknown nature (on this topic see Soddy 1904b , Chap. XI entitled “The energy of radio-active change”, pp. 165–170).

Soddy ( 1953 , f 282, 2, line 6).

In this science fiction novel, H. G. Wells predicts, about 20 years in advance, the discovery of artificial radioactivity, the industrial use of atomic energy and a global conflict resulting from the use of “atomic bombs”, with the devastation of the main cities of the planet (Wells 1914 ).

See the 6th paragraph and Cioci ( 2008 ).

Soddy ( 1915 , p. 13, line 19).

The Sydney Morning Herald ( 1935 , f 124, line 43).

Soddy ( 1949 , p. 128, column 1, line 52). For the significant contribution made by Soddy to economics, linked to his commitment to the prevention of war, see Cioci ( 2009a ).

Heavy water was considered to be slow motion par excellence because deuterium has a light nucleus, suitable to subtract kinetic energy from neutrons, and being already formed by a neutron and a proton it was believed to be not “inclined” to absorb neutrons. The research started eventually in Montreal after the war with construction of the atomic pile ZEEP, the origin of the CANDU reactors.

F. Rasetti ( 1958–1968 , p. 11, line 2). Information about this document can be found in Amaldi ( 1990 , p. 175, footnote 15). The document was widely quoted by Battimelli and De Maria in the “Preface” of Amaldi ( 1997 ) and by Maltese ( 2003 ).

Ivi, line 4.

Battimelli ( 2002 ), Maltese ( 2003 ). These authors reported Edoardo Amaldi’s assessments; he considered the decision to work in the Manhattan Project as a necessary assumption of responsibility by scientists to prevent the world being conquered by the Nazis using nuclear weapons: “If I had found myself there (in front of this dramatic dilemma), after deep and painful considerations on which it was my moral duty of man asked to decide whether cooperate in the defense of democracies … or lock myself in my private life, doing nothing to fight the dictatorship, I would have eventually opted for the first solution” (Amaldi 1997 , p. 98, line 32).

Amaldi ( 1979 , p. 199, column 2, line 13).

Associated Press ( 1933 , p. 1, line 18). A summary of the presentation at the British Association is published in the Times of September 12, 1933, p. 7 and of Nature, no. 132, pp. 432–433 (16 September 1933).

Szilard ( 1972 , pp. 729–732; 1978, pp. 45–46).

E. Amaldi ( 1984 , p. 160, line 27).

The exact critical mass for uranium 235 is 52 kg. The critical mass for plutonium 239 is 10 Kg.

Frisch and Peierls ( 1940b , p. 86, line 15).

United States Atomic Energy Commission ( 1971 , p. 12, line 4).

Weisskopf ( 1967 , p. 40, column 1, line 19; 42, column 1, line 11).

Smyth ( 1945 , p. 254, line 16).

Rotblat ( 1985 , p. 18, line 22).

Committee on Social and Political Implications ( 1946 , p. 3, column 3, line 34).

Oppenheimer ( 1948 , p. 66, line 45).

The account of A. K. Smith is entitled “A peril and a Hope” by a famous expression of Oppenheimer according to which nuclear weapons would constitute a danger and a hope for humanity because given the power of these terrible means of destruction humankind would have to give up war to settle international disputes and would have to create a united world under the law and humanity.

Smith and Weiner ( 1980 ).

Oppenheimer ( 1966 , line 20).

Lilienthal et al. ( 1946 , p. 24, line 15).

For further arguments in favour of this conclusion see Cioci ( 2004 ).

General Advisory Committee ( 1949 , p. 155, line 39).

Ivi, line 21.

Ibidem, 156, line 6.

See Capuozzo and Cioci ( 2010 ).

E.g. see: Teller ( 1950 ).

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Acknowledgments

I thank Professor Giovanni Battimelli, Referent for Documents and Sources for the History of Physics, Department of Physics, University “La Sapienza” of Rome, who helped me in the consultation of the Edoardo Amaldi Archives.

My special thanks is addressed to Colin Harris, Superintendent of the Special Collections Reading Rooms, for his help in finding the unpublished writings of Frederick Soddy , to Dr. Chris Fletcher, Keeper of Special Collections, and to the Bodleian Library, Oxford University, which owns them, for permission given on the basis of ‘non-exclusive rights’ to quote and to paraphrase them.

I am grateful to Bonnie Coles for helping me in the examination and retrieval of the writings of Robert Oppenheimer at the Manuscript Division of the Library of Congress (USA).

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Vincenzo Cioci

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Cioci, V. (2015). On the History and Technology of the Atomic Bomb. The Commitment of the Scientists. In: Pisano, R. (eds) A Bridge between Conceptual Frameworks. History of Mechanism and Machine Science, vol 27. Springer, Dordrecht. https://doi.org/10.1007/978-94-017-9645-3_7

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• History Day Topic Guide: Atomic Bomb - Hiroshima & Nagasaki

History Day Topic Guide: Atomic Bomb - Hiroshima & Nagasaki: Home

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The ruins of Nagasaki Medical College, Japan, 1945.

In 1942, just months after the United States entered World War II, a secret program, the Manhattan Project was created under the command of Brigadier General Leslie Groves and the scientific direction of J. Robert Oppenheimer.  British and American scientists began developing a new kind of weapon, an atomic bomb.  By July 1945 the weapons were ready to be used against the one remaining Axis nation, Japan (the war in Europe ended with the surrender of Germany on May 8, 1945).

On the clear morning of August 6, 1945 a single plane, the Enola Gay, made it's way across southern Japan to the city of Hiroshima and dropped an uranium bomb nicknamed "Little Boy."  In an instant the city was leveled and and estimates of those killed by the blast and its aftermath range from 70,000 to over 200,000.  Three days later, on August 9, the  plutonium bomb nicknamed "Fat Man"  was dropped on the city of Nagasaki.  Casualty estimates range from 40,000 to 70,000 dead.  On August 10, 1945 Japan offered to surrender to the United States and the Allies. World War II ended.

Historians continue to debate the rationale behind the decision to drop the atomic bombs on Japan.  Were the bombs necessary?  What would have been the human costs of an invasion of Japan? What role did the entrance of the Soviet Union into the Pacific War play?  Did racism have an affect on the decision? 

For more background information on the bombing of Hiroshima and Nagasaki see:

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70 years after Hiroshima, opinions have shifted on use of atomic bomb

On Aug. 6, 1945, the United States dropped an atomic bomb on the Japanese city of Hiroshima, killing tens of thousands of people – many instantly, others from the effects of radiation. Death estimates range from 66,000 to 150,000 .

This first use of a nuclear weapon by any nation has long divided Americans and Japanese. Americans have consistently approved of this attack and have said it was justified. The Japanese have not. But opinions are changing: Americans are less and less supportive of their use of atomic weapons, and the Japanese are more and more opposed.

In 1945, a Gallup poll immediately after the bombing found that 85% of Americans approved of using the new atomic weapon on Japanese cities. In 1991, according to a Detroit Free Press survey conducted in both Japan and the U.S., 63% of Americans said the atomic bomb attacks on Japan were a justified means of ending the war, while only 29% thought the action was unjustified. At the same time, only 29% of Japanese said the bombing was justified, while 64% thought it was unwarranted.

But a 2015 Pew Research Center survey finds that the share of Americans who believe the use of nuclear weapons was justified is now 56%, with 34% saying it was not. In Japan, only 14% say the bombing was justified, versus 79% who say it was not.

Not surprisingly, there is a large generation gap among Americans in attitudes toward the bombings of Hiroshima. Seven-in-ten Americans ages 65 and older say the use of atomic weapons was justified, but only 47% of 18- to 29-year-olds agree. There is a similar partisan divide: 74% of Republicans but only 52% of Democrats see the use of nuclear weapons at the end of World War II as warranted.

In the years since WWII, two issues have fueled a debate over America’s use of nuclear weapons against Japan: Did Washington have an alternative to the course it pursued – the bombing of Hiroshima followed by dropping a second atomic weapon on Nagasaki on Aug. 9 – and should the U.S. now apologize for these actions?

In September 1945, the National Opinion Research Center at the University of Chicago asked Americans what they would have done if they had been the one to decide whether or not to use the atomic bomb against Japan. At the time, a plurality of Americans supported the course chosen by the Truman administration: 44% said they would have bombed one city at a time, and another 23% would have wiped out cities in general – in other words, two-thirds would have bombed some urban area. Just 26% would have dropped the bomb on locations that had no people. And only 4% would not have used the bomb.

By 1995, 50 years after Hiroshima and Nagasaki, support for an alternative to the bombing had grown. Gallup asked Americans whether, had the decision been left up to them, they would have ordered the bombs to be dropped, or tried some other way to force the Japanese to surrender. Half the respondents said they would have tried some other way, while 44% still backed using nuclear weapons.

But this decline in American support for the use of atomic bombs against Japanese cities did not mean Americans thought they had to apologize for having done so. In that same Gallup survey, 73% said the U.S. should not formally apologize to Japan for the atom bomb attacks on Hiroshima and Nagasaki. Only 20% supported an official apology.

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Creation of the U.S. atomic weapons program

Manhattan project expansion under groves and oppenheimer, the first atomic bombs: trinity, hiroshima, and nagasaki, operation crossroads and the end of the manhattan project.

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In 1939, American scientists, many of whom had fled from fascist regimes in Europe, were aware of advances in nuclear fission and were concerned that Nazi Germany might develop a nuclear weapon. The physicists Leo Szilard and Eugene Wigner persuaded Albert Einstein to send a letter to U.S. President Franklin D. Roosevelt warning him of that danger and advising him to establish an American nuclear research program. The Advisory Committee on Uranium was set up in response. The beginning of the Manhattan Project can be dated to December 6, 1941, with the creation of the Office of Scientific Research and Development, headed by Vannevar Bush .

American physicist J. Robert Oppenheimer headed the Manhattan Project, with the goal of developing the atomic bomb , and Edward Teller was among the first recruited for the project. Leo Szilard and Enrico Fermi built the first nuclear reactor . Ernest Orlando Lawrence was program chief in charge of the development of the electromagnetic process of separating uranium-235 .

Other notable researchers included Otto Frisch , Niels Bohr , Felix Bloch , James Franck , Emilio Segrè , Klaus Fuchs , Hans Bethe , and John von Neumann . The person who oversaw the Manhattan Project, however, was not a scientist. He was Leslie Groves , a brigadier general in the U.S. Army.

The Manhattan Project produced the first atomic bomb . Several lines of research were pursued simultaneously . Both electromagnetic and fusion methods of separating the fissionable uranium-235 from uranium-238 were explored at Oak Ridge in Tennessee. The production of plutonium-239, first achieved at the University of Chicago , was further pursued at the Hanford Engineer Works in Washington state. In the meantime, at Los Alamos , New Mexico, scientists found a way to bring the fissionable material to supercritical mass (and thus explosion) and to control the timing and devised a weapon to house it. The first test, on July 16, 1945, at Alamogordo air force base in New Mexico, produced a massive nuclear explosion.

Although many physicists were opposed to the actual use of the atomic bomb created by the Manhattan Project, U.S. President Harry S. Truman believed that the bomb would persuade Japan to surrender without requiring an American invasion. Accordingly, on August 6, 1945, a U.S. airplane dropped an atomic bomb on Hiroshima , killing at least 70,000 people instantly (tens of thousands more died later of radiation poisoning). Three days later, another U.S. aircraft dropped a bomb on Nagasaki . Since then, a number of countries have concluded that possession of nuclear arms is the best way to guarantee their safety, despite fears that nuclear proliferation increases the chances of the use of such a weapon.

Manhattan Project , U.S. government research project (1942–45) that produced the first atomic bombs . See Britannica’s interactive timeline of the Manhattan Project.

American scientists, many of them refugees from fascist regimes in Europe, took steps in 1939 to organize a project to exploit the newly recognized fission process for military purposes. The first contact with the government was made by G.B. Pegram of Columbia University , who arranged a conference between Enrico Fermi and the Navy Department in March 1939. In the summer of 1939, Albert Einstein was persuaded by his fellow scientists to use his influence to present the military potential of an uncontrolled fission chain reaction to Pres. Franklin D. Roosevelt . In February 1940, $6,000 was made available to start research under the supervision of a committee headed by L.J. Briggs, director of the National Bureau of Standards (later National Institute of Standards and Technology ). On December 6, 1941, the project was put under the direction of the Office of Scientific Research and Development, headed by Vannevar Bush .

After the U.S. entered World War II , the War Department was given joint responsibility for the project, because by mid-1942 it was obvious that a vast array of pilot plants, laboratories, and manufacturing facilities would have to be constructed by the U.S. Army Corps of Engineers for the assembled scientists to carry out their mission. In June 1942 the Corps of Engineers’ Manhattan District was initially assigned management of the construction work (because much of the early research had been performed at Columbia University, in Manhattan ), and in September 1942 Brig. Gen. Leslie R. Groves was placed in charge of all Army activities (chiefly engineering activities) relating to the project. “Manhattan Project” became the code name for research work that would extend across the country.

It was known in 1940 that German scientists were working on a similar project and that the British were also exploring the problem. In the fall of 1941 Manhattan Project chemist Harold C. Urey accompanied Pegram to England to attempt to set up a cooperative effort, and by 1943 a combined policy committee was established with Great Britain and Canada . In that year a number of British and Canadian scientists moved to the United States to join the project.

If the project were to achieve timely success, several lines of research and development had to be carried on simultaneously before it was certain whether any might succeed. The explosive materials then had to be produced and be made suitable for use in an actual weapon.

Uranium-235 , the essential fissionable component of the postulated bomb, cannot be separated from its natural companion, the much more abundant uranium-238 , by chemical means; the atoms of these respective isotopes must rather be separated from each other by physical means. Several physical methods to do this were intensively explored, and two were chosen—the electromagnetic process developed at the University of California , Berkeley , under Ernest Orlando Lawrence and the diffusion process developed under Urey at Columbia University. Both of these processes, particularly the diffusion method, required large, complex facilities and huge amounts of electric power to produce even small amounts of separated uranium-235. Philip Hauge Abelson developed a third method called thermal diffusion, which was also used for a time to effect a preliminary separation. These methods were put into production at a 70-square-mile (180-square-km) tract near Knoxville , Tennessee , originally known as the Clinton Engineer Works, later as Oak Ridge .

Only one method was available for the production of the fissionable material plutonium-239 . It was developed at the metallurgical laboratory of the University of Chicago under the direction of Arthur Holly Compton and involved the transmutation in a reactor pile of uranium-238. In December 1942 Fermi finally succeeded in producing and controlling a fission chain reaction in this reactor pile at Chicago.

Quantity production of plutonium-239 required the construction of a reactor of great size and power that would release about 25,000 kilowatt-hours of heat for each gram of plutonium produced. This required the development of chemical extraction procedures that would work under conditions never before encountered . An intermediate step in putting this method into production was taken with the construction of a medium-size reactor at Oak Ridge. The large-scale production reactors were built on an isolated 1,000-square-mile (2,600-square-km) tract on the Columbia River north of Pasco , Washington—the Hanford Engineer Works .

Before 1943, work on the design and functioning of the bomb itself was largely theoretical, based on fundamental experiments carried out at a number of different locations. In that year a laboratory directed by J. Robert Oppenheimer was created on an isolated mesa at Los Alamos , New Mexico , 34 miles (55 km) north of Santa Fe . This laboratory was tasked with developing methods to reduce the fissionable products of the production plants to pure metal and fabricate the metal to required shapes. Methods of rapidly bringing together amounts of fissionable material to achieve a supercritical mass (and thus a nuclear explosion) had to be devised , along with the actual construction of a deliverable weapon that would be dropped from a plane and fused to detonate at the proper moment in the air above the target. Most of these problems had to be solved before any appreciable amount of fissionable material could be produced, so that the first adequate amounts could be used at the fighting front with minimum delay.

By the summer of 1945, amounts of plutonium-239 sufficient to produce a nuclear explosion had become available from the Hanford Works, and weapon development and design were sufficiently advanced so that an actual field test of a nuclear explosive could be scheduled. Such a test was no simple affair. Elaborate and complex equipment had to be assembled to provide a complete diagnosis of success or failure. By this time the original $6,000 authorized for the Manhattan Project had grown to $2 billion.

The first atomic bomb was exploded at 5:30 am on July 16, 1945, at the Alamogordo air base 120 miles (193 km) south of Albuquerque , New Mexico. Oppenheimer had called the site “Trinity” in reference to one of John Donne ’s Holy Sonnets . The bomb—a plutonium implosion device called Gadget —was raised to the top of a 100-foot (30-meer) steel tower that was designated “Zero.” The area at the base of the tower was marked as “Ground Zero,” a term that would pass into common parlance to describe the center of an (often catastrophic) event. The tower was surrounded by scientific equipment, with remote monitoring taking place in bunkers occupied by scientists and a few dignitaries 10,000 yards (9 km) away. The explosion came as an intense light flash, a sudden wave of heat, and later a tremendous roar as the shock wave passed and echoed in the valley. A ball of fire rose rapidly, followed by a mushroom cloud extending to 40,000 feet (12,200 meters). The bomb generated an explosive power equivalent to 15,000 to 20,000 tons of trinitrotoluene (TNT); the tower was completely vaporized and the surrounding desert surface fused to glass for a radius of 800 yards (730 meters).

The following month, two other atomic bombs produced by the project, the first using uranium-235 and the second using plutonium, were dropped on the Japanese cities of Hiroshima and Nagasaki. Neither city had been attacked during the U.S. strategic bombing campaign until that point, and planners wished to demonstrate the destructive power of the bombs. Hiroshima was selected as the primary target because of its military value; the city served as the headquarters of the Japanese Second Army. On August 6, 1945, at about 8:15 am local time, a U.S. B-29 bomber released a gun assembly fission bomb—dubbed Little Boy —above Hiroshima. The weapon detonated at an altitude of 1,900 feet (580 meters), and the explosive yield was estimated to be the equivalent of 15,000 tons of TNT. Some 70,000 people were killed instantly, and by the end of the year the death toll had surpassed 100,000. Two-thirds of the city area was destroyed.

By the morning of August 9, 1945, the Soviet Union had declared war on Japan, but the Japanese government had not yet communicated its intent to surrender to the Allies . A B-29 carrying Fat Man —a plutonium implosion bomb similar to the one used in the Trinity test—was initially dispatched to Kokura (now part of Kitakyūshū , Japan). Thick clouds and haze over Kokura prevented the bombardier from sighting the designated aimpoint, however, and the bomber proceeded to its secondary target, the port city of Nagasaki . At 11:02 am Fat Man exploded at an altitude of 1,650 feet (500 meters) northwest of the city center. The bomb detonated with the explosive force of 21,000 tons of TNT. An estimated 40,000 people were killed instantly, and at least 30,000 more would die from their injuries and radiation poisoning by the end of the year. About 40 percent of the city’s buildings were completely destroyed or severely damaged. Due to the area’s uneven terrain, a significant part of Nagasaki—particularly in the southeastern industrial and government district—was relatively unscathed . The Japanese initiated surrender negotiations the next day. By this point, Groves had notified U.S. Pres. Harry S. Truman that another bomb would be ready for delivery within a week.

On September 2, 1945, a Japanese delegation signed formal surrender documents on the deck of the USS Missouri . Shortly after the conclusion of hostilities, Manhattan Project physicist Philip Morrison traveled to Hiroshima at the request of the War Department to study the effects of the atomic bomb. Characterizing the bomb as “preeminently a weapon of saturation,” he said, “It destroys so quickly and so completely such a large area that defense is hopeless.” Horrified by what he had witnessed , Morrison would spend the rest of his life campaigning against nuclear weapons and a potential “third bomb.”

After the war, the Manhattan Project oversaw Operation Crossroads, a military-scientific experiment conducted at Bikini atoll in the South Pacific in 1946. “Able,” the first peacetime atomic weapons test, was carried out on July 1, 1946. In attendance were some 42,000 U.S. military personnel, as well as more than 100 journalists and representatives from a dozen foreign countries. A 20-kiloton atomic bomb was dropped from a B-29 and exploded at an altitude of about 520 feet (158 meters) over a fleet of about 80 decommissioned World War II naval vessels. Only five ships were sunk by the blast, and, although several more were damaged, the majority survived the explosion relatively unscathed. Within a day, radiation levels had subsided enough for the ships to be boarded and inspected. Press and foreign military observers seemed underwhelmed that the blast had not vaporized the assembled ships, but such an appraisal discounted the debilitating effect that radiation would have had on a ship’s crew. Many test animals placed throughout the fleet quickly succumbed to radiation sickness , confirming a prediction in the Bulletin of the Atomic Scientists that “a large ship, about a mile away from the explosion, would escape sinking, but the crew would be killed by the deadly burst of radiations from the bomb, and only a ghost ship would remain, floating unattended on the vast waters of the ocean.”

The second test, “Baker,” took place on July 25, 1946. A 23-kiloton device was suspended at a depth of 90 feet (27 meters) from a decommissioned landing craft in the Bikini lagoon. At the moment of the explosion, a luminous dome rose on the surface of the lagoon, followed by an opaque cloud that enveloped about half the target area. The cloud dissipated within seconds, revealing a column of ascending water that lifted the 26,000-ton battleship USS Arkansas into the air for a brief moment. The column of water, some 2,200 feet (670 meters) in diameter, rose to a height of 1 mile (1.6 km), sending spray still higher. The expanding column of spray engulfed about half the ships in the target fleet with radioactive water. Waves traveling outward from the explosion were up to 100 feet (30 meters) tall, even at a distance of 1,000 feet (some 300 meters) from the epicenter . The evaluation board of the Joint Chiefs of Staff reported that the explosion had produced intense radioactivity in the waters of the lagoon. The target ships were saturated with radioactive water so lethal that four days after the test, it was still unsafe for inspection parties to spend “any useful length of time” in the center of the target area or on any of the ships anchored there. Persistent radiation and the difficulty of decontamination led to the cancellation of “Charlie,” a planned third test that would have involved a bomb being detonated at the bottom of the Bikini lagoon.

After the conclusion of Operation Crossroads, the Manhattan District relinquished direction of the plants and laboratories under its jurisdiction to the U.S. Atomic Energy Commission (AEC), a civilian agency established by act of Congress in August 1946. Under the AEC, weapon development and testing continued along with development of the peaceful uses of atomic energy . The U.S. government disbanded the AEC under the Energy Reorganization Act of 1974 and divided its functions between two new agencies: the Nuclear Regulatory Commission , which regulates the nuclear power industry, and the Energy Research and Development Administration, which was eliminated in 1977 when the Department of Energy was created.

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Science News

How understanding nature made the atomic bomb inevitable.

A chain reaction of basic discoveries preceded the bombing of Hiroshima 75 years ago

By Tom Siegfried

Contributing Correspondent

August 6, 2020 at 6:00 am

75 years ago, on August 6, 1945, the United States dropped an atomic bomb on Hiroshima, Japan (shown). Three days later, another was dropped on Nagasaki.

509th Operations Group/Wikimedia Commons

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Atomic bombs hastened the end of World War II. But they launched another kind of war, a cold one, that threatened the entire planet with nuclear annihilation. So it’s understandable that on the 75th anniversary of the atomic bomb explosion that devastated Hiroshima (August 6, 1945), reflections tend to emphasize the geopolitical dramas during the decades that followed.

But it’s also worth reflecting on the scientific story of how the bombs came to be.

It’s not easy to pinpoint that story’s beginning. Nuclear fission — the source of the bomb’s energy — was discovered in 1938 , less than seven years before Hiroshima. But the science behind nuclear energy originated decades earlier. You could say 1905, when Einstein revealed to the world that E = mc 2 . Or perhaps it’s better to begin with Henri Becquerel’s discovery of radioactivity in 1896. Radioactivity revealed a new sort of energy, of vast quantity, hidden within the most minuscule components of matter — the parts that made up atoms.

In any case, once science began to comprehend the subatomic world, no force could stop the eventual revelation of the atom’s power.

But the path from basic science to the bomb was not straightforward. There was no clear clue to how subatomic energy could be tapped for any significant use, military or otherwise. Writing in Science News Bulletin (the original Science News precursor) in 1921, physicist Robert Millikan noted that a gram of radium, in the process of disintegrating into lead, emits 300,000 times as much energy as burning a gram of coal. That wasn’t scary, Millikan said, because there wasn’t even enough radium in the world to make very much popcorn. But, he warned, “it is almost a foregone conclusion that similar stores of energy are also possessed by the atoms which … are not radioactive.”

In 1923 editor Edwin Slosson of Science News-Letter (the immediate precursor to Science News ) also remarked that “all the elements have similar stores of energy if we only know how to release it.” But so far, he acknowledged, “scientists have not been able to unlock the atomic energy except by the employment of greater energy from another source.”

By then, physicists realized that the atom’s wealth of energy was stored in a nucleus — discovered by Ernest Rutherford in 1911 . But accessing nuclear energy for practical use seemed unfeasible — at least to Rutherford, who in 1933 said that anyone planning to exploit nuclear energy was “talking moonshine.” But just the year before, the tool for releasing nuclear power had been discovered by James Chadwick , in the form of the subatomic particle known as the neutron.

Having no electric charge, the neutron was the ideal bullet to shoot into an atom, able to penetrate the nucleus and destabilize it. Such experiments in Italy by Enrico Fermi in the 1930s did actually induce fission in uranium. But Fermi thought he had created new, heavier chemical elements. He had no idea that the uranium nucleus had split. He concluded that he had produced a new element , number 93, heavier than uranium (element 92).

Not everyone agreed. Ida Noddack, a German chemist-physicist , argued that the evidence was inconclusive, and Fermi might have produced lighter elements, fragments of the uranium nucleus. But she was defying the prevailing wisdom. As the German chemist Otto Hahn wrote years later, the idea of breaking a uranium nucleus into smaller pieces was “wholly incompatible with the laws of atomic physics. To split heavy atomic nuclei into lighter ones was then considered impossible.”

Nevertheless Hahn and Lise Meitner, an Austrian physicist , continued bombarding uranium with neutrons, producing what they too believed to be new elements. Soon Meitner had to flee Germany for Sweden to avoid Nazi persecution of Jews. Hahn continued the work with chemist Fritz Strassmann; in December 1938 they found that an element they thought was radium could not be chemically distinguished from barium — apparently because it was barium. Hahn and Strassmann couldn’t explain how that could be.

Hahn wrote of this result to Meitner, who discussed it with her nephew Otto Frisch, a physicist studying at Niels Bohr’s institute in Copenhagen. Meitner and Frisch figured out what happened — the neutron had induced the uranium nucleus to split. Barium was one of the leftover chunks. Frisch told Bohr, about to board a ship to America, who realized instantly that fission confirmed his belief that an atomic nucleus behaved analogously to a drop of liquid. Upon arrival in the United States, Bohr began collaborating with John Archibald Wheeler at Princeton to explain the fission process. They quickly found that fission occurred much more readily in uranium-235, the rare form, than in the more common uranium-238. And their analysis revealed that an as yet undiscovered element, number 94, would also be especially efficient at fissioning. Their paper appeared on September 1, 1939, the day Germany invaded Poland to begin World War II.

Between Bohr’s arrival in Amer­ica in January 1939 and the publication of his paper with Wheeler, news of fission’s reality spread, stunning physicists and chemists around the world. At the end of January, for instance, word of fission reached Berkeley, where the leading physicist was J. Robert Oppenheimer, who eventually became the scientist that led the Manhattan Project to build the bomb.

Among the attendees at the Berkeley seminar introducing fission was Glenn Seaborg, a young chemistry in­structor (who in 1941 discovered the unknown element 94 predicted by Bohr and Wheeler, naming it plutonium). Seaborg recalled that at first Oppenheimer didn’t believe fission happened. But, “after a few minutes he decided it was possible,” Seaborg said in a 1997 interview. “It just caught every­body by surprise.”

After the initial surprise, physicists quickly established that fission was the key to unlocking the atom’s energy storehouse. “Lots of people verified that indeed when ura­nium is bombarded by neutrons, slow neutrons in particular, a process occurs which releases tremen­dous amounts of energy,” physicist Hans Bethe said in a 1997 interview. Soon the implications for warfare occupied everybody’s attention.

“The threat of war was getting closer and closer,” Wheeler said in an interview in 1985. “It was impossible not to think about what this business (fission) could mean in the event of war.” In early 1939, physicists meeting to discuss fission concurred that a fission bomb was thinkable. “Everybody agreed that it was perfectly pos­sible to make a nuclear explosive,” Bethe remembered.

Concerns that Germany might develop a nuclear bomb prompted Albert Einstein’s famous letter to President Franklin Roosevelt , sent in August 1939, that eventually led to the Manhattan Project. It became clear that building a fission bomb would require generating a “chain reaction” — the fission process itself would need to release neutrons capable of inducing further fission. In December 1942, Fermi led the team at the University of Chicago that demonstrated a sustained chain reaction , after which work on the bomb proceeded in Los Alamos, N.M., under Oppenheimer’s direction.

At first some physicists thought a bomb could not be developed rapidly enough to be relevant to the war. Bethe, for instance, preferred to work on radar.

“I had considered the whole enterprise a boon­doggle,” he said. “I thought this had nothing to do with the war.” But by April 1943 Oppenheimer succeeded in recruiting Bethe to Los Alamos. By that time the science was in place, and the path to designing and building a bomb was straightforward. “All we had to do was to find out that there were no unforeseen difficulties,” Bethe said.

Ultimately the prototype was exploded at Alamogordo in July 1945, about three weeks before the bomb’s use against Japan.

It was a weapon more horrifying than anything humankind had ever encountered or imagined. And science was responsible. But only because science succeeded in understanding nature more deeply than before. Nobody knew at first where that understanding would lead.

There was absolutely no way to foresee that the discovery of radioactivity, or the atomic nucleus, or even the neutron would eventually enable the construction of a weapon of mass destruction. Yet once it was known that a bomb was possible, it was inevitable.

After Germany’s surrender in World War II, the Allies detained several top German scientists, including Werner Heisenberg, leader of the Nazi bomb project, and eavesdropped on their conversations. It was clear that the Germans failed to build a bomb because they did not think it was practically possible. But after hearing of the bombing of Hiroshima, Heisenberg was quickly able to figure out how the bomb had, in fact, been feasible. Once scientists know for sure something is possible, it’s a lot easier to do it.

In the case of the atomic bomb, basic research seeking nature’s secrets initiated a chain reaction of new knowledge, impossible to control. So the mushroom cloud that resulted symbolizes one of science’s most disturbing successes.

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Home — Essay Samples — War — Atomic Bomb

Essays on Atomic Bomb

When it comes to writing an essay about the atomic bomb, there are numerous topics to choose from. The use of the atomic bomb during World War II remains one of the most controversial and debated events in history. The decision to drop the bomb on Hiroshima and Nagasaki has sparked numerous discussions and arguments about its ethical, moral, and political implications. In this article, we will explore some of the most popular and intriguing essay topics related to the atomic bomb

The decision to drop the atomic bomb

One of the most common essay topics related to the atomic bomb is the decision-making process behind dropping the bomb on Japan. This topic allows for a thorough examination of the events leading up to the decision, the reasons behind it, and the consequences that followed. By incorporating these keywords strategically throughout the essay, it can rank higher in search engine results and attract more readers.

The moral and ethical implications of the atomic bomb

Another popular essay topic is the moral and ethical considerations surrounding the use of the atomic bomb. This topic delves into the ethical dilemmas faced by the decision-makers, the civilian casualties, and the long-term effects of nuclear warfare. Incorporating these keywords into the essay will make it more visible to readers searching for information on the ethical aspects of the atomic bomb.

The impact of the atomic bomb on Japan

This essay topic focuses on the immediate and long-term impact of the atomic bomb on Japan. It explores the destruction caused by the bomb, the human suffering, and the subsequent efforts at recovery and reconstruction. By incorporating these keywords strategically, the essay can attract more readers interested in learning about the impact of the atomic bomb on Japan.

The role of science and technology in the development of the atomic bomb

This essay topic examines the scientific and technological advancements that led to the creation of the atomic bomb. It explores the role of physicists, engineers, and researchers in developing the bomb, as well as the ethical considerations surrounding scientific innovation. By incorporating these keywords into the essay, it can attract readers interested in the scientific and technological aspects of the atomic bomb.

The legacy of the atomic bomb in the modern world

This essay topic explores the lasting impact of the atomic bomb on international relations, nuclear proliferation, and global security. It examines the lessons learned from the use of the bomb, as well as the ongoing efforts to prevent the use of nuclear weapons. By incorporating these keywords strategically, the essay can rank higher in search engine results and attract more readers interested in the modern implications of the atomic bomb.

There are numerous essay topics related to the atomic bomb that offer an opportunity to explore its historical, ethical, and scientific complexities. Whether examining the decision to drop the bomb, its moral implications, its impact on Japan, the role of science and technology, or its legacy in the modern world, there are plenty of opportunities to create insightful and compelling essays about the atomic bomb.

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• 26 July 2023

Why Oppenheimer has important lessons for scientists today

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Director Christopher Nolan’s ambitious, three-hour film Oppenheimer , about the US theoretical physicist who led the development of the world’s first nuclear weapons, opened in UK and US cinemas on 21 July to widespread acclaim. Since the film’s release, the scientific world has been abuzz about its accuracy — and whether it does justice to the many facets of the story of the atomic bomb.

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July 21, 2023

What Was the Manhattan Project?

The top-secret Manhattan Project resulted in the atomic bombs dropped on the Japanese cities of Hiroshima and Nagasaki in 1945

By Tom Metcalfe

Sign marking the explosion of the test of the atomic bomb at the Trinity site, N.M.

Education Images/Universal Images Group via Getty Images

The Manhattan Project was a top-secret program to make the first atomic bombs during World War II. Its results had profound impacts on history: the subsequent nuclear arms race has radically changed the political world order in ways that are still evident today.

Thousands of scientists, including theoretical physicist J. Robert Oppenheimer , took part in the Manhattan Project, often while they and their families were lodged at secret military bases in remote locations. It resulted in the two atomic bombs dropped on the Japanese cities of Hiroshima and Nagasaki in August 1945, which brought World War II to its end and probably killed more than 100,000 people .

“The Manhattan Project harnessed the enormous energy in the nucleus of the atom for the first time,” explains Cynthia Kelly, founder and president of the Atomic Heritage Foundation, a nonprofit dedicated to the history of the project and the atomic age.

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One of the project’s consequences was the creation of terrifying opposing arsenals of nuclear weapons . But it also resulted in innovations from medicine to space exploration and in the science and engineering of civilian nuclear energy, Kelly says.

The U.S. Army Corps of Engineers created the Manhattan Engineer District in June 1942 to hide the development of the atomic bomb during the war—hence that effort’s name of the “Manhattan Project.”

But historian of science Alex Wellerstein explains in an online overview that the project originated in an idea from the late 1930s—that Nazi Germany might build an atomic bomb, so the U.S. should do so first. Historical records reveal that Germany didn’t get far , but the prospect of a Nazi bomb was horrifyingly real.

Several leading researchers worked for wartime Germany, including Werner Heisenberg . Even so, many scientists who favored an American atom bomb, including Hungarian-born physicist Leo Szilard , had fled the Nazis in Europe. had fled the Nazis in Europe. 

In July 1939 Szilard and others enlisted the help of the renowned physicist Albert Einstein , then on holiday on Long Island, N.Y., to support them by writing a letter to President Franklin D. Roosevelt. The Einstein-Szilard letter , as it’s known, changed history. It prompted Roosevelt to convene a committee to investigate the possibility of building an atomic bomb, and 1941 this group became a new committee to  lay the groundwork for the full project.

These early stages involved key contributions from the U.K. and Canada. But in the end, the atomic bomb was mostly an American weapon.

After 1942 the Manhattan Project was the recognized Allied effort to build an atomic bomb. It mainly used uranium ore from a mine in what is now the Democratic Republic of the Congo, which was kept secret from the Germans.

Otherwise the project was conducted in the U.S., primarily at three top-secret towns: Oak Ridge, Tenn., where uranium was enriched until it was radioactive enough for nuclear fission; Hanford, Wash., where reactors transformed uranium into plutonium, an even more powerful nuclear fuel; and Los Alamos, N.M., where Oppenheimer directed the laboratory that designed and built experimental atomic bombs.

There were also dozens of smaller sites . And officials went to extraordinary lengths to keep it all secret.

World War II historian Alexandra Levy says most of the more than 600,000 people involved—including the thousands of scientists, engineers and technicians who worked on the weapons, as well as construction workers and the people who kept the three secret towns going—were deliberately not told their purpose.

“Most of those people did not know that the goal of the project was to build a new type of bomb,” Levy says. “Today, between the Internet and social media, it’s difficult to imagine such a large-scale endeavor remaining secret for long.”

Kelly adds, “We live in a very, very different world. Aside from one or two key senators agreeing to a blank check for the Manhattan Project, Congress and the press were kept in the dark. That would be impossible today.”

The Manhattan Project culminated in the Trinity test in New Mexico on July 16, 1945—the first detonation of a nuclear weapon. By that time, the U.S. had spent around $2.2 billion —the equivalent of around $37 billion today.

But the dangers of a Nazi bomb had faded, and Japan was now the designated target. Although Japan never had an atomic bomb program, the idea of stopping its aggression with a show of awful destruction became fixed among Manhattan Project leaders, science historian Wellerstein says.

He notes that Oppenheimer, then the charismatic director of the Los Alamos laboratory, twice voted in favor of the initial atomic bomb attack on Hiroshima —which killed tens of thousands of civilians—instead of a purely military target.

Oppenheimer is seen as essential to the success of the American atomic bomb project. “He contributed to some of the early scientific breakthroughs of the project,” Levy says. “His great gift was bringing together scientists, engineers and other technicians to collaborate on and solve problems.”

But Oppenheimer was also ambivalent about its results. In recalling his experience at the Trinity test in 1965, he quoted a story from the Hindu scripture the Bhagavad Gita about a prince, reluctant to kill his enemies, who witnessed the transformation of Krishna, an incarnation of the Hindu deity Vishnu: “ Now I am become Death, the destroyer of worlds .”

Oppenheimer was the reluctant prince, not Krishna. “He didn’t want to kill people,” Wellerstein says. “But he knew that nuclear weapons were going to be built anyway, and he felt that he had a duty to do this horrible thing.”

Faculty of Humanities

The bertrand russell research centre, the atomic bomb, introduction.

The Bertrand Russell Research Centre is offering an electronic version of an edition-in-progress of Russell’s first anti-nuclear writing. The electronic version has a range of hypertext capabilities woven into the traditional Collected Papers structure of headnote, chronology, text, annotation, textual notes, bibliographical index, and sometimes illustrations. Maroon-coloured passages link to bidirectional annotations; green passages, to bidirectional textual notes. It is hoped this feature will prove both inobtrusive and useful.

Russell’s paper “The Atomic Bomb” (published as “The Bomb and Civilization”) was written in 1945. The editor of this paper, which is scheduled to be in Volume 24, is Kenneth Blackwell. Let him know of any errors. A conventional view of the headnote, paper and apparatus as they are to be printed in the edition is available in PDF format. This view is searchable, saveable, and printable.

This article, as Dr. Blackwell states in the headnote, is Russell’s first response to the news of the devastation caused by the first atomic bomb. Though written hurriedly, and in a frantic moment of history, it announces themes that will dominate Russell’s political programme for years to come. The article announces the urgency of the search for a structure of world peace, and it reiterates his faith in scientific progress and his hope that the United States will assume leadership in creating the global structures that are necessary for the survival of the human race. Russell’s mood is one which combines the composure of the sage and the panic of the prophetic Cassandra. As a man of science he wishes to reassure the public concerning the scientific achievement. He advises his readers that “The atomic bomb embodies the results of a combination of genius and patience as remarkable as any in the history of mankind”, that the men whose work made this bomb possible were for the most part “both high-minded and public spirited”, and finally that we should not look upon the bomb as a punishment “for impiety in inquiring too closely into the hidden secrets of nature”. On the contrary he reaffirms his faith that “Science is capable of conferring enormous boons.”

But the panic is equally vivid. Russell is clearly convinced that now that the weapon has been unleashed, a war for the possession of uranium is almost inevitable. Even before the war has ended, Russell is convinced of the outbreak of rivalry between the wartime Allies, the United States and the Soviet Union. He is convinced that another war is inevitable. After proposing and then dismissing the alternative of a Hobbesian contract in which all the nations of the world surrender their power and constitute a world government, or the next best solution, an American putsch in which, armed with the only available atomic weapons, the government of the United States will set up a world government by force (a programme which he advocated since the closing stage of the First World War), he ends with the hope that after the next world war “some one Power will emerge with such preponderant strength as to be able to establish a peaceful hegemony over the rest of the globe.”

Louis Greenspan (1934–2018) Past Director, Russell Editorial Project

“The Atomic Bomb” (1945)

Textual Notes

Bibliographical index.

The atom-bombing of Hiroshima on 6 August 1945 destroyed four square miles of the city. Three days later Russell was at work on this article. We know this because midway he remarks that he has just learned of the explosion of the second atomic bomb, over Nagasaki. This bomb was dropped about 2 a.m. GMT ( Weintraub 1995 , 482; Ham 2012 , 364). He abandons the exposition and history of atomic theory to dwell on the danger to civilization posed by the new weaponry, and immediately states: “The prospect for the human race is sombre beyond all precedent…. A great deal of new political thinking will be necessary if utter disaster is to be averted.” This is in contrast to the guarded optimism of paper 48 , finished a few days prior to the nuclear attack on Japan and perhaps, as a consequence, not published. In the last sentence quoted, Russell began using language that would occur repeatedly as he wrote about the prospect of nuclear warfare. In a cognate paper a month later ( 61 ) he wrote, “we must learn a new kind of political thinking” (324: 17–18). When the Soviets exploded their first atomic bomb, he gave a new paper the title “The Bomb: Can Disaster Be Averted?” ( 1949d ). In “Man’s Peril” he wrote: “All, equally, are in peril, and, if the peril is understood, there is hope that they may collectively avert it. We have to learn to think in a new way” ( 1954a ; Papers 28 : 86). He closely reiterated these lines in the Russell–Einstein Manifesto ( ibid ., 28: 318).

Russell does not refer to the Manhattan project by name, although he may well have been cognizant of the physicists’ pre-war curiosity about producing an atomic explosion. By the time of writing he knew of the 1938 discovery of nuclear fission and that scientists on both sides of World War II had been working on the problem. Newspapers carried this information in early days of the nuclear age (see The Times 1945q and, there officially on the bomb’s origins, Churchill 1945a ) . The Times covered military and scientific aspects extensively ( 1945p , 1945r , 1945s ) . Some of Russell’s information may have come from these sources.

The main outline and some details of his international policy for the next few years are visible, complete with an argument for forcing world government and a prediction that the U.S. would not internationalize the atomic secrets.

Russell could not comment here on whether the atomic bomb hastened the end of the war. Japan did not surrender until several days later, on 14 August. At the same time preparations were under way for massive Allied land invasions ( Giangreco 2017 ). It remains uncertain whether it was the atomic bomb or the prospect of the invasions, including that of the Russians, which brought Japan to surrender. It was “a common observation that Japan at war’s end was vastly weaker than anyone outside the country had imagined—or anyone inside it had acknowledged” ( Dower 1999 , 44). However, this is not ( Giangreco’s conclusion (see his 2017 , xvii–xix).

The copy-text is a photocopy and scan of the manuscript, which Russell titled “The Atomic Bomb” (RA3 Rec. Acq. 840). The manuscript survived in the papers of Forward ’s editor, Emrys Hughes (1894–1969; soon to be elected M.P. at this time). Its survival as the marked-up copy for the compositor is unusual in this volume. Additional changes were made, possibly to save space. There is no evidence that Russell read proofs of the newspaper publication, of which he kept two copies. Manuscript and print were collated. Several departures from Russell’s manuscript were made, none of which is accepted here. The substitution in the printed text of “hear” for the manuscript’s “learn” was a misreading of Russell’s hand, as was “expelled” for “repelled”. Forward silently deleted several commas in typesetting Russell’s manuscript, and others were inserted. The substantive variants are recorded in the Textual Notes .

Chronology (selected)

The Atomic Bomb (published as “The Bomb and Civilization”, 18 Aug. 1945)

Uranium, the element chiefly used in the atomic bomb, has the heaviest and most complex of atoms. Normally there are 92 planetary electrons, while the nucleus is made up of about 238 neutrons (which have mass without electricity), 238 positrons (which have positive electricity and very little mass) and 146 electrons, which are like positrons except that their electricity is negative. Positrons repel each other, and so do electrons; but a positron and electron attract each other. The overcrowding of mutually attracted and repelled particles in the tiny space of the uranium nucleus involves enormous potentially explosive forces. Uranium is slightly radio-active, which means that some of its atoms break up naturally. But a quicker process than this is required for the making of an atomic bomb.

Rutherford found out, about thirty years ago, that little bits could be chipped off an atom by bombardment. In 1939 a more powerful process was discovered: it was found that neutrons , entering the nucleus of a uranium atom, would cause it to split into two roughly equal halves, which would rush off and disrupt other uranium atoms in the neighbourhood, and so set up a train of explosions so long as there was any of the right kind of uranium to be encountered.

Ever since the beginning of the war, the Germans on the one side, and the British and Americans on the other, have been working on the possibility of an atomic explosive. One of the difficulties was to make sure that it would not be too effective: there was a fear that it might destroy not only the enemy, but the whole planet, and naturally experiments were risky. But the difficulties were overcome, and now the possibility which scientists have foreseen for over forty years has entered into the world of practical politics. The labours of Rutherford and Bohr , of Heisenberg and Schrödinger , and a number of other distinguished men, the ablest men of our time, and most of them both high-minded and public-spirited, have borne fruit: in an instant, by means of one small bomb , every vestige of life throughout four square miles of a populous city has been exterminated. As I write, I learn that a second bomb has been dropped on Nagasaki.

The prospect for the human race is sombre beyond all precedent. Mankind are faced with a clear-cut alternative: either we shall all perish, or we shall have to acquire some slight degree of common sense. A great deal of new political thinking will be necessary if utter disaster is to be averted.

For the moment, fortunately, only the United States is in a position to manufacture atomic bombs. The immediate result must be a rapid end to the Japanese war, whether by surrender or by extermination . The power of the United States in international affairs is, for the time being, immeasurably increased; a month ago , Russia and the United States seemed about equal in warlike strength, but now this is no longer the case. This situation, however, will not last long, for it must be assumed that before long Russia and the British Empire will set to work to make these bombs for themselves. Uranium has suddenly become the most precious of raw materials, and nations will probably fight for it as hitherto they have fought for oil. In the next war , if atomic bombs are used on both sides, it is to be expected that all large cities on both sides will be completely wiped out; so will all scientific laboratories and all governmental centres. Communications will be disrupted, and the world will be reduced to a number of small independent agricultural communities living on local produce, as they did in the Dark Ages. But presumably none of them will have either the resources or the skill for the manufacture of atomic bombs.

There is another and a better possibility, if men have the wisdom to make use of the few years during which it will remain open to them. Either war or civilization must end, and if it is to be war that ends, there must be an international authority with the sole power to make the new bombs. All supplies of uranium must be placed under the control of the international authority , which shall have the right to safeguard the ore by armed forces. As soon as such an authority has been created, all existing atomic bombs, and all plants for their manufacture, must be handed over to it . And of course the international authority must have sufficient armed forces to protect whatever has been handed over to it. If this system were once established, the international authority would be irresistible, and wars would cease. At worst, there might be occasional brief revolts that would be easily quelled.

But I fear all this is Utopian. The United States will not consent to any pooling of armaments, and no more will Soviet Russia. Each will insist on retaining the means of exterminating the other, on the ground that the other is not to be trusted.

If America were more imperialistic there would be another possibility, less Utopian and less desirable, but still preferable to the total obliteration of civilized life. It would be possible for Americans to use their position of temporary superiority to insist upon disarmament, not only in Germany and Japan, but everywhere except in the United States, or at any rate in every country not prepared to enter into a close military alliance with the United States, involving compulsory sharing of military secrets. During the next few years, this policy could be enforced; if one or two wars were necessary, they would be brief, and would soon end in decisive American victory. In this way a new League of Nations could be formed under American leadership, and the peace of the world could be securely established. But I fear that respect for international justice will prevent Washington from adopting this policy.

In view of the reluctance of mankind to form voluntarily an effective international authority, we must hope, and perhaps we may expect, that after the next world war some one Power will emerge with such preponderant strength as to be able to establish a peaceful hegemony over the rest of the globe. The next war, unless it comes very soon, will endanger all civilized government; but if any civilized government survives and achieves supremacy, there will again be a possibility of ordered progress and of the utilization of science for happiness rather than for destruction.

One is tempted to feel that Man is being punished, through the agency of his own evil passions, for impiety in inquiring too closely into the hidden secrets of Nature. But such a feeling is unduly defeatist. Science is capable of conferring enormous boons: it can lighten labour, abolish poverty, and enormously diminish disease. But if science is to bring benefits instead of death, we must bring to bear upon social, and especially international, organization, intelligence of the same high order that has enabled us to discover the structure of the atom. To do this effectively we must free ourselves from the domination of ancient shibboleths, and think freely, fearlessly, and rationally about the new and appalling problems with which the human race is confronted by its conquest of scientific power.

• Atoms In The ABC of Atoms ( 1923a ), 9–10, Russell writes in much the same detail and with the same figures about the minuteness of atoms. He predicted of nuclear research that “It is probable that it will ultimately be used for making more deadly explosives and projectiles than any yet invented” ( 1923a , 11; quoted by Wood 1957 , 152).
• Rutherford Ernest Rutherford (1871–1937), New Zealand-born British physicist. He was Professor of Physics at McGill University 1898–1907, when he left for Manchester. He won the Nobel Prize for chemistry in 1908. In 1919 he became director of the Cavendish Laboratory in Cambridge.
• more powerful process Lise Meitner and O.R. Frisch concluded that the results of experiments done by the German chemist, Otto Hahn, in December 1938 could only have been obtained as the result of nuclear fission. Frisch verified their assumption with experiments done in Copenhagen in January 1939 ( Ham 2012 , 101–2).
• the Germans on the one side, and the British and Americans German research was led by Werner Heisenberg. The British and Americans at first worked separately, but during the Quebec Conference of August 1943 it was agreed they would work together. In 1951 Russell was to boast (his own word) of the British contribution and could not think of any Americans who had “contributed anything of any great importance at this stage” ( Papers 26 : 502).
• foreseen for over forty years 1905 was the year of publication of Einstein’s special theory of relativity. Wittner ( 1993 , 4) discusses H.G. Wells’ The World Set Free ( 1914a ), which depicts a war fought with nuclear weapons.
• Bohr Niels Bohr (1885–1962), Danish physicist, worked with Rutherford at Manchester before returning to Denmark. After escaping from Denmark in late 1943, he spent the remainder of World War II in the United States working on the Manhattan project. Bohr later favoured the internationalization of atomic weapons. Russell had gotten to know Bohr well on the former’s 1935 Scandinavian lecture tour. Indeed, Bohr tutored Russell at that time in quantum physics and indeterminism ( Stevenson 2011 , 115, 117).
• Heisenberg Werner Karl Heisenberg (1901–1976), German physicist. With Max Born, he worked in quantum mechanics, proposing the uncertainty principle in the 1920s. He won the Nobel Prize for physics in 1932. Russell got to know him in Copenhagen in 1935 ( Stevenson 2011 , 121n.1), and made his acquaintance again at a meeting on 3 March 1948 at the Master’s Lodge, Christ’s College, Cambridge. They corresponded and cooperated over Pugwash in the 1950s.
• Schrödinger Erwin Schrödinger (1887–1961), Austrian physicist. He won the Nobel Prize for physics in 1933 and left Germany for Oxford the same year. He spent World War II in Dublin. Russell and Schrödinger later corresponded.
• one small bomb Some British “Blockbuster” bombs, and especially the “Grand Slam”, weighed more than “Little Boy”, the uranium bomb that destroyed Hiroshima. This bomb weighed 9,700 pounds and was ten feet long with a diameter of 28 inches. Russell’s point, of course, concerns the size of the bomb relative to its target. New was the much greater explosive power (15–20 kilotons) of the “small bomb” and the slightly greater power of the plutonium bomb that levelled much of Nagasaki. It was also a fission bomb. In November 1945, in a House of Lords speech (paper 66 , 1945 , Russell forecast the development of the fusion bomb. For his still developing early views on thermonuclear weapons, see Papers 26 : lxii–lxiv, 85. He was later to write ( 1961d  ) on the U.S.S.R.’s 50-megaton hydrogen bomb, the most powerful yet exploded.
• every vestige of life throughout four square miles It was three days before photographic evidence was made public. Cf. the headline in The Times : “Hiroshima Inferno; 4 Square Miles Obliterated; Huge Death Roll” ( 1945r ). Devastation outside the city centre was not total, and lingering deaths from the survivors’ radiation sickness were yet to come ( Ham 2012 , Chap. 21).
• surrender or by extermination. Emperor Hirohito decided Japan should surrender on 10 August 1945, but the Japanese military did not agree to do so until 14 August. See Weinberg 1994 , 890, and Weintraub 1995 , Chap. 33. For the last severe months of the war of atrocity with Japan, see Beevor 2012 , 772–4.
• a month ago This was a reasonable belief at the time, since contested. In early July 1945 the U.S.S.R. had as yet no Far Eastern military presence to speak of but was overwhelmingly strong in Eastern Europe, Austria and East Germany. The U.S. was rapidly defeating the Japanese forces, except on the home islands Kyushu and Honshu, and was redirecting its troops from Europe to the planned invasion of Japan. Both the U.S.S.R. and U.S. had reached a peak of conventional weapons production. Thus in all factors considered together, they might have seemed equal in “warlike strength” before the explosion of America’s plutonium test bomb on 16 July 1945. It was the distribution of their respective strengths that was very unequal.
• British Empire Since 1931 the empire’s dominions and colonies had been known as the British Commonwealth of Nations (and from 1949 the Commonwealth of Nations). Russell began referring to it as “the British Commonwealth” in 1947, in which year India became a self-governing dominion.
• make these bombs for themselves The U.S. Atomic Energy Act (1946; in effect 1 Jan. 1947) restricted the exchange of information on atomic energy, thus reducing Anglo-American cooperation, even though Roosevelt and Churchill had agreed on it. On 8 January 1947 Attlee and his cabinet secretly authorized the manufacture of a British atomic bomb. The first British atomic test was on 3 October 1952. The Soviets exploded their first atomic bomb on 29 August 1949. They had been working separately on a bomb and accelerated their programme after Potsdam.
• control of the international authority One such authority that developed in the next two years was the Atomic Development Authority. See the papers 70a ( B&R B85), 73 ( B&R C47.12), where Russell discusses the A.D.A. See also in this volume ( Papers 24) the annotation at A121:14.
• League of Nations Although the United Nations Organization did not come into existence until 24 October 1945, the founding San Francisco Conference had been over since 25 June and the Charter signed on the 26th. Russell, who was critical of the veto power on the Security Council, appears here to dismiss the U.N.O.
• ordered progress Russell often invoked this faith of his youth: “We believed in ordered progress by means of politics and free discussion” ( Russell 1967 , 1: 70). See, e.g., 379 in this volume and Papers 13 : 137.

The links in the textual notes are to the passages in green type in Russell’s final text.

The copy-text is a photocopy plus a colour scan (RA3 Rec. Acq. 840) of the manuscript (“CT”) in the Emrys Hughes papers, National Library of Scotland. It is foliated 1, 2–8, seems to measure 211 x 268 mm., and is written in ink. An editorial hand rewrote, none too clearly, more than three dozen of Russell’s words in decipherment for the compositor. The same hand (or hands—sometimes with a blue pencil) added fifteen paragraph breaks and the instruction “Double Column”, all of which are ignored here. “45” is the publication, “The Bomb and Civilization”, Forward , Glasgow, 39, no. 33 (18 Aug. 1945): 1, 3. It has six section heads, also ignored here as non-authorial; so is a pair of non-Russellian-drawn commas around the restrictive clause “which scientists have foreseen for over forty years”.

• The hydrogen … scale. CT] inserted in lighter (blue rather than blue-black) ink at foot of leaf
• about CT] inserted
• repelled CT] expelled 45
• atomic CT] atom 45
• little CT] inserted
• off 45] of CT
• neutrons CT] above deleted positrons
• Schrödinger CT] Schrodinger 45
• learn CT] hear 45
• , if atomic bombs are used on both sides, it is to be expected that all large cities on both sides CT] replaced it is to be expected that all large cities on both sides < reiteration of on both sides deleted in pencil editorially and omitted in 45>
• over to it . CT] over. 45 struck through editorially in pencil>
• perhaps CT] perhaps 45
• will again be CT] will be 45
• of the utilization CT] the utilization 45
• of CT] written over &

Instead of page numbers, links are provided to the references to these citations.

• BEEVOR, ANTONY, 2012 . The Second World War . New York: Little, Brown and Company. Referred to: surrender
• BLACKWELL, KENNETH, and HARRY RUJA, B&R . A Bibliography of Bertrand Russell . 3 vols. London: Routledge, 1994. Referred to: headnote , control of the international authority
• CHURCHILL, WINSTON, 1945a . “Britain’s Share; Statement by Mr. Churchill”. 7 Aug., p. 4. Referred to: headnote
• DOWER, JOHN W., 1999 . Embracing Defeat: Japan in the Wake of World War II . New York: W.W. Norton. Referred to: headnote
• GIANGRECO, D.M., 2017. Hell to Pay: Operation Downfall and the Invasion of Japan, 1945–47 . Revised edition. Annapolis, MD: Naval Institute Press. Referred to: headnote
• HAM, PAUL, 2012 . Hiroshima Nagasaki . London: Doubleday. Referred to: headnote , more powerful process , vestige of life
• RUSSELL, BERTRAND, 1923a . The ABC of Atoms . London: Kegan Paul, Trench, Trubner. (B&R A45) (Russell’s library.) Referred to: atoms
• —— 1945 “The International Situation”. Parliamentary Debates , Lords, (5), 138 (28 Nov. 1945): cols. 87–92. Referred to: one small bomb
• —— 1949d .“The Bomb: Can Disaster Be Averted?”. Unpublished ms. RA1 220.019200. Referred to: headnote
• —— 1954a . “Man’s Peril from the Hydrogen Bomb”. The Listener , 52 (30 Dec.): 1,135–6. (B&R C54.35) Reprinted as “Man’s Peril” in 1956 and as 16 in Papers 28 . Referred to: headnote
• —— 1956 . Portraits from Memory and Other Essays . London: George Allen and Unwin. (B&R 102) (Russell’s library.) Referred to: Man’s Peril
• —— 1961d . “Thoughts on the 50-Megaton Bomb” New Statesman , 62 (3 Nov.): 638. (B&R C61.40) Referred to: one small bomb
• —— 1967. The Autobiography of Bertrand Russell. Vol. 1: 1872–1914. (B&R A142.1a) London: George Allen and Unwin. Referred to: ordered progress
• —— Papers 13. Prophecy and Dissent, 1914–16 . Edited by Richard A. Rempel et al. (The Collected Papers of Bertrand Russell, Vol. 13.) (B&R AA6) London: Unwin Hyman, 1988. Referred to: ordered progress
• —— Papers 26. Cold War Fears and Hopes, 1950–52 . Edited by Andrew G. Bone. (The Collected Papers of Bertrand Russell, Vol. 26.) (B&R AA20) London: Routledge, 2020. Referred to: the Germans , one small bomb
• —— Papers 28. Man’s Peril, 1954–55 . Edited by Andrew G. Bone. (The Collected Papers of Bertrand Russell, Vol. 28.) (B&R AA16) London: Routledge, 2003. Referred to: headnote
• STEVENSON, MICHAEL D., 2011 . “ ‘No Poverty, Much Comfort, Little Wealth’: Bertrand Russell’s 1935 Scandinavian Tour”” . Russell , 31 (2011): 101–40. Referred to: Bohr , Heisenberg
• THE TIMES , London, 1945p . “First Atom Bomb Hits Japan”. 7 Aug., p. 4. Referred to: headnote
• —— 1945q . “The New Chemistry”; Releasing the Energy That Runs the Sun; Atomic Bombs Explained”. 8 Aug., p. 5. Referred to: headnote
• —— 1945r . “Hiroshima Inferno; 4 Square Miles Obliterated; Huge Death Roll”. 9 Aug., p. 4. Referred to: headnote , vestige of life
• —— 1945s . “Atom Bomb on Nagasaki; Second City Hit; Fleet Attack on Honshu”. 10 Aug., p. 4. Referred to: headnote
• WEINBERG, GERHARD L., 1994 . A World at Arms: A Global History of World War II . Cambridge: Cambridge University Press. Referred to: surrender
• WEINTRAUB, STANLEY, 1995 . The Last Great Victory: The End of World War II July/August 1945 . New York: Dutton. Referred to: headnote , surrender
• WELLS, H.G., 1914a . The World Set Free . London: Macmillan. Referred to: foreseen
• WITTNER, LAWRENCE S., 1993 . The Struggle against the Bomb . Vol. I: One World or None: A History of the World Nuclear Disarmament Movement through 1953 . Stanford, Calif.: Stanford University Press. Referred to: headnote , foreseen
• WOOD, ALAN, 1957 . Bertrand Russell, the Passionate Sceptic . London: George Allen & Unwin. (Russell’s library.) Referred to: Atoms

Beyond the bomb: Atomic research changed medicine, biology

Princeton University historian Angela Creager spent more than a decade researching early efforts to transform knowledge and technology developed for the Manhattan Project to peaceful uses. The research culminated in a new book, "Life Atomic: Radioisotopes in Science and Medicine," which details how that effort made possible important breakthroughs in medicine and biology.

Video stills from Nick Barberio, Office of Communications

Even before the end of World War II, scientists working on the Manhattan Project saw a future for their work beyond military might. 

A new book by Princeton University historian Angela Creager explains how knowledge and technology that grew out of the secret U.S.-led effort to build atomic bombs delivered on that promise — making possible important breakthroughs in medicine and biology. 

In this video , Creager discusses those breakthroughs and how they happened.

Play the "Insights With Angela Creager" video.

"Generally when both ordinary people and scholars have thought about the legacy of the Manhattan Project, we thought about the way in which physics and engineering were put to military use. We thought about a destructive legacy, the arms race, the Cold War," said Creager, the Philip and Beulah Rollins Professor of History . "Part of what I discovered was that atomic energy had just as much of a legacy in some of the fields we think of as peaceable as it did in military uses."

The book, "Life Atomic: Radioisotopes in Science and Medicine," is the culmination of more than a decade of research by Creager, who traveled across the country to study unpublished government documents and the papers of scientists involved in military and civilian research.

Creager, who joined the Princeton faculty in 1994, teaches undergraduate and graduate courses on the history of science, the history of biology, gender and science, and technology and science. In 1998, she received the President's Award for Distinguished Teaching at Princeton. Creager is also the author of "The Life of a Virus: Tobacco Mosaic Virus as an Experimental Model, 1930-1965." She is a fellow of the American Association for the Advancement of Science and president of the History of Science Society. Creager earned a Ph.D. from the University of California-Berkeley and a bachelor's degree from Rice University.

Among the breakthroughs linked to atomic research that Creager highlights in "Life Atomic":

• treatments for cancer, especially using cobalt-60;
• diagnostic tests still used widely in medicine;
• an understanding of metabolic pathways, such as that for photosynthesis;
• a clearer picture of how the human body absorbs and uses substances such as iron;
• the modern understanding of ecosystems as environments in which matter and energy flow through living and nonliving components.

These advances were made possible by the availability of radioisotopes, which are radioactive isotopes, or variants, of stable atoms. In the post-World War II era, the U.S. government produced radioisotopes in some of the same nuclear reactors that had been built to produce material for nuclear weapons. The radioisotopes were promoted by the government and sold at a discount to laboratories, hospitals and companies, Creager said.

Radioisotopes quickly gained acceptance as both medical therapies and radiotracers, she said.

"Tracer uses are when you replace one atom of a compound with a particular radiolabeled atom so that you can follow that label through the ordinary chemical or biological processes the compound goes through," Creager said. "So radiotracing was very widely applicable to study biochemistry, physiology, endocrinology and eventually ecology. Basically anything where a chemical compound is in motion, radiotracing is a way to look at change over time, and look at chemical transformations."

Creager said the study of photosynthesis offered a good example of how radiotracing was used. Researchers grew algae in a glass container exposed to bright light. They added carbon dioxide labeled with the radioisotope carbon-14 and let the algae take up some of the carbon dioxide. They then examined how the radiolabeled carbon had moved from one compound to another through the chemical reactions of photosynethsis.

"Even by the late 1940s, it was already apparent this could be used to crack open the photosynthetic pathway, which really hadn't been understood before," Creager said.

In a similar way, animals, and later humans, were fed food containing a radioisotope of iron in experiments that aided the understanding of iron uptake, Creager said.

The book also traces changes in the perceptions of scientists and the public about the risks of radiation. An investigation by a presidential panel in the 1990s detailed the ways in which research subjects — sometimes without their knowledge — were exposed to radiation during the postwar period. This included, for instance, pregnant women in experiments with radioiron. Creager said documents declassified in the wake of that investigation aided her research.

"Now we think the government should be involved at some level in protecting civilians from exploitation by a medical establishment that is eager for research subjects, but in the 1950s the thought was that physicians should be trusted to regulate themselves," Creager said. "The human research using radioisotopes wasn't atypical of other types of medical research at the time, even though we may look back and think it was a really bad idea."

Creager's research has carried over to the classroom. For example, she once taught a junior seminar titled "Atomic Legacies." As part of the class, eight students traveled with Creager to the National Archives outside Washington, D.C., for two days of research.

"The junior papers that were produced from this seminar were terrific, and it was also a great experience to go with them to the archives and, in many cases, have the students encounter unpublished sources for the first time and think about how they might go into writing a historical account," Creager said.

Creager's research for "Life Atomic" was supported by grants from the National Science Foundation, the National Institutes of Health, the National Endowment for the Humanities and Princeton University.

She has begun work on her next project, which examines changing ideas about environmental carcinogens from the 1960s through the 1980s. Many of those ideas, she said, were first shaped by research on radiation.

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Bravo specializes in the history of photography and art history. Creager's scholarship examines 20th-century biomedical research. Morimoto's work focuses on nuclear history, culture and memory.

Algal library lends insights into genes for photosynthesis .

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'Insights With Angela Creager' .

A new book by Princeton University historian Angela Creager explains how knowledge and technology that grew out of the Manhattan Project paved the way for important breakthroughs in medicine and biology. In this video, Creager describes the great hopes for atomic research in the 1940s and '50s and how those hopes were later tempered by  concerns about radiation exposure.

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National Museum of Nuclear Science & History

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National Archives News

The Atomic Bombing of Hiroshima and Nagasaki, August 1945

Photograph of Hiroshima after the atomic bomb. (National Archives Identifier 22345671 )

The United States bombings of the Japanese cities of Hiroshima and Nagasaki on August 6 and August 9, 1945, were the first instances of atomic bombs used against humans, killing tens of thousands of people, obliterating the cities, and contributing to the end of World War II. The National Archives maintains the documents that trace the evolution of the project to develop the bombs, their use in 1945, and the aftermath.

Online Exhibits

The Atomic Bombing of Hiroshima and Nagasaki   features a letter written by Luis Alvarez, a physicist who worked on the Manhattan Project, on August 6, 1945, after the first atomic bomb was dropped on Hiroshima, Japan.

[Photograph: The atomic cloud rising over Nagasaki, Japan, August 9, 1945. National Archives Identifier 535795 ]

A People at War looks at the 509 Composite Group, the unit selected to carry the atomic bomb to Hiroshima.

[Photograph: Col. Paul Tibbets, Jr., waves from the cockpit of the Enola Gay before departing for Hiroshima, August 6, 1945. National Archives Identifier  535737 ]

Photograph Gallery

"Little Boy" atomic bomb being raised into plane on Tinian Island before the flight to Hiroshima. National Archives Identifier  76048583

Hiroshima after the atomic bomb. National Archives Identifier  22345671

Hiroshima after the atomic bomb. National Archives Identifier  22345679

Hiroshima after the atomic bomb. National Archives Identifier  22345680

Hiroshima after the atomic bomb. National Archives Identifier  148728174

Nuclear weapon of the "Fat Man" type, the kind detonated over Nagasaki, Japan. National Archives Identifier  175539928

The atomic cloud rising over Nagasaki, Japan. National Archives Identifier  535795

Nagasaki after the atomic bomb. National Archives Identifier  39147824

Nagasaki after the atomic bomb. National Archives Identifier  39147850

Additional Photographs

Atomic Bomb Preparations at Tinian Island, 1945

Photographs used in the report Effects of the Atomic Bomb on Hiroshima, Japan

Manhattan Project Notebook

Atomic bomb/Enola Gay preparations for the bombing missions

Post-bombing aerial and on-the-ground images of Hiroshima

Empty bottle of Chianti Bertolli wine signed by scientists who worked on the Manhattan Project

Archival Film

Hiroshima and Nagasaki Effects, 1945

The Last Bomb ,  a 1945 film, done in Technicolor, by the Army Air Forces Combat Camera Units and Motion Picture Units covering the B-29 bombing raids on Japan

Effects on the human body of radiation from the atomic bomb

Additional Records

Photos: Atomic Bomb Preparations at Tinian Island, 1945

Atomic bomb/ Enola Gay preparations for the bombing missions

Post-Hiroshima bombing aerial and on-the-ground images

Color image of Hiroshima after bombing

Manhattan Project records from Oak Ridge, TN

Blogs and Social Media Posts

Unwritten Record:  Atomic Bombings of Hiroshima and Nagasaki

Unwritten Record:  Witness to Destruction: Photographs and Sound Recordings Documenting the Hiroshima Bombing

Forward with Roosevelt:  Found in the Archives: The Einstein Letter

Pieces of History:  Little Boy: The First Atomic Bomb

Pieces of History:  Harry Truman and the Bomb

Pieces of History:  Morgantown Ordnance Works (part of the Manhattan Project) Panoramas, 1940–1942

Today's Document:  Petition from Manhattan Project Scientists to President Truman

For Educators

Docs Teach resources on the atomic bomb

Teaching with Documents:  Photographs and Pamphlet about Nuclear Fallout

Kennedy Library: “The Presidency in the Nuclear Age”

At the Presidential Libraries

Roosevelt Library: Albert Einstein’s letter to FDR regarding the atomic bomb

Truman Library: “The Decision to Drop the Atomic Bomb ”

Truman Library: Additional records on the bombing of Hiroshima

Truman Library:  President Truman's Diary Entry for July 17, 1945 (the day before Truman learned that the United States had successfully tested the world's first atomic bomb)

Truman Library: Memo for the Record, Manhattan Project, July 20, 1945

Truman Library: Petition from Leo Szilard and other scientists to President Truman

Eisenhower Library: Atoms for Peace

Kennedy Library: “ The Presidency in the Nuclear Age: The Race to Build the Bomb and the Decision to Use It”