Chronology of the Decision to Use the BombChronology of the Decision to Use the BombThe official order states: The official order states:

"The 509 Composite Group, 20th Air Force will deliver "The 509 Composite Group, 20th Air Force will deliver its first special bomb as soon as the weather will its first special bomb as soon as the weather will

permit visual bombing after about 3 August 1945 on permit visual bombing after about 3 August 1945 on one of the targets: Hiroshima, Kokura, Niigata, and one of the targets: Hiroshima, Kokura, Niigata, and

Nagasaki."Nagasaki."

Yi-Ren Chen | Hist 5N | April 11th 2004

March 25March 25 At the urging of Leo Szilard, Albert Einstein signs a letter of introdAt the urging of Leo Szilard, Albert Einstein signs a letter of introd

uction of Szilard to President Roosevelt. Szilard wishes to warn uction of Szilard to President Roosevelt. Szilard wishes to warn Roosevelt of the post-war dangers of a nuclear arms race if the atRoosevelt of the post-war dangers of a nuclear arms race if the atomic bomb is used against Japan. The letter states: “The terms omic bomb is used against Japan. The letter states: “The terms of secrecy under which Dr. Szilard is working at present do not pof secrecy under which Dr. Szilard is working at present do not permit him to give me information about his work; however, I undermit him to give me information about his work; however, I understand that he now is greatly concerned about the lack of adequerstand that he now is greatly concerned about the lack of adequate contact between scientists who are doing this work and thosate contact between scientists who are doing this work and those members of your Cabinet who are responsible for formulating e members of your Cabinet who are responsible for formulating policy.” In the memorandum accompanying the letter, Szilard policy.” In the memorandum accompanying the letter, Szilard wrote: “our ‘demonstration’ of atomic bombs will precipitatwrote: “our ‘demonstration’ of atomic bombs will precipitate a race in the production of these devices between the United Ste a race in the production of these devices between the United States and Russia and that if we continue to pursue the present coates and Russia and that if we continue to pursue the present course, our initial advantage may be lost very quickly in such a race.urse, our initial advantage may be lost very quickly in such a race.””

April 12 April 12 Franklin Roosevelt dies, and Harry Truman becomes the 33rd PreFranklin Roosevelt dies, and Harry Truman becomes the 33rd Pre

sident of the United States.sident of the United States. April 25 April 25 Secretary of War Stimson and General Groves brief President TruSecretary of War Stimson and General Groves brief President Tru

man on the bomb. In this briefing, Groves insists that Japan had man on the bomb. In this briefing, Groves insists that Japan had always been the target of the bomb’s use.always been the target of the bomb’s use.

April 25 April 25 Joint Chief Planners advise Joint Chiefs of Staff that “unless a dJoint Chief Planners advise Joint Chiefs of Staff that “unless a d

efinition of unconditional surrender can be given which is acceptefinition of unconditional surrender can be given which is acceptable to the Japanese, there is no alternative to annihilation and able to the Japanese, there is no alternative to annihilation and no prospect that the threat of absolute defeat will bring about cano prospect that the threat of absolute defeat will bring about capitulation.”pitulation.”

April 27April 27 The Target Committee meets for the first time to decide The Target Committee meets for the first time to decide

which Japanese cities to target with the atomic bomb. By which Japanese cities to target with the atomic bomb. By the end of May the following cities are selected: Kyoto, the end of May the following cities are selected: Kyoto, Hiroshima, Kokura and Niigata. [See minutes of the second Hiroshima, Kokura and Niigata. [See minutes of the second meeting of the Target Committee in Related Sites.] meeting of the Target Committee in Related Sites.] Eventually Kyoto is replaced by Nagasaki and the listed Eventually Kyoto is replaced by Nagasaki and the listed cities are spared further conventional bombing by the cities are spared further conventional bombing by the American Army Air Force.American Army Air Force.

April 29April 29 In a report entitled Unconditional Surrender, the Joint In a report entitled Unconditional Surrender, the Joint

Intelligence Committee informs the Joint Chiefs of Staff that Intelligence Committee informs the Joint Chiefs of Staff that “numbers of informed Japanese, both military and civilian, “numbers of informed Japanese, both military and civilian, already realize the inevitability of absolute defeat.”already realize the inevitability of absolute defeat.”

May 8May 8 War in Europe ends.War in Europe ends.

May 9May 9 The Interim Committee meets for the first time. Its purpose is “tThe Interim Committee meets for the first time. Its purpose is “t

o study and report on the whole problem of temporary war contro study and report on the whole problem of temporary war controls and later publicity, and to survey and make recommendationols and later publicity, and to survey and make recommendations on post war research, development and controls, as well as legis on post war research, development and controls, as well as legislation necessary to effectuate them.” The Interim Committee slation necessary to effectuate them.” The Interim Committee appoints a Scientific Panel, which included Oppenheimer, Lawreappoints a Scientific Panel, which included Oppenheimer, Lawrence, Fermi and Compton.nce, Fermi and Compton.

May 25 May 25 Leo Szilard visits White House with letter of introduction from AlLeo Szilard visits White House with letter of introduction from Al

bert Einstein to warn President Truman of the dangers atomic wbert Einstein to warn President Truman of the dangers atomic weapons pose for the post-War world and to urge him not to authoeapons pose for the post-War world and to urge him not to authorize use of atomic weapons against Japan. Szilard is referred Matrize use of atomic weapons against Japan. Szilard is referred Matthew J. Connelly, Truman’s appointments secretary, to James thew J. Connelly, Truman’s appointments secretary, to James Byrnes in Spartanburg, South Carolina.Byrnes in Spartanburg, South Carolina.

May 28May 28 Assistant Secretary of War John J. McCloy argues to Secretary of War StiAssistant Secretary of War John J. McCloy argues to Secretary of War Sti

mson that the term “unconditional surrender” should be dropped: “mson that the term “unconditional surrender” should be dropped: “Unconditional surrender is a phrase which means loss of face and I wonUnconditional surrender is a phrase which means loss of face and I wonder whether we cannot accomplish everything we want to accomplish in der whether we cannot accomplish everything we want to accomplish in regard to Japan without the use of that term.”regard to Japan without the use of that term.”

May 28May 28 In a State Department Memorandum of Conversation, Acting Secretary In a State Department Memorandum of Conversation, Acting Secretary

of State Joseph Grew describes a meeting with President Truman that dof State Joseph Grew describes a meeting with President Truman that day. Grew writes: “The greatest obstacle to unconditional surrender by tay. Grew writes: “The greatest obstacle to unconditional surrender by the Japanese is their belief that this would entail the destruction or permhe Japanese is their belief that this would entail the destruction or permanent removal of the Emperor and the institution of the Throne. If some anent removal of the Emperor and the institution of the Throne. If some indication can now be given the Japanese that they themselves, when oindication can now be given the Japanese that they themselves, when once thoroughly defeated and rendered impotent to wage war in the futunce thoroughly defeated and rendered impotent to wage war in the future will be permitted to determine their own future political structure, thre will be permitted to determine their own future political structure, they will be afforded a method of saving face without which surrender will ey will be afforded a method of saving face without which surrender will be highly unlikely.”be highly unlikely.”

May 31May 31 The Interim Committee agrees that “the most desirable target The Interim Committee agrees that “the most desirable target

would be a vital war plant employing a large number of workers would be a vital war plant employing a large number of workers and closely surrounded by workers’ houses.” Among those agand closely surrounded by workers’ houses.” Among those agreeing is James Conant, the president of Harvard University.reeing is James Conant, the president of Harvard University.

May 31May 31 The Office of Strategic Services (OSS) reports on receiving a JapaThe Office of Strategic Services (OSS) reports on receiving a Japa

nese peace feeler through a Japanese diplomat stationed in Portnese peace feeler through a Japanese diplomat stationed in Portugal. The Japanese diplomat says that the actual terms are uniugal. The Japanese diplomat says that the actual terms are unimportant so long as the term “unconditional surrender” is not mportant so long as the term “unconditional surrender” is not used.used.

June 1June 1 Interim Committee makes formal decision decides not to warn tInterim Committee makes formal decision decides not to warn t

he civilian populations of the targeted cities.he civilian populations of the targeted cities.

June 11June 11 The Franck Committee on the social and political implications of The Franck Committee on the social and political implications of

the atomic bomb, headed by Nobel Laureate James Franck, issues the atomic bomb, headed by Nobel Laureate James Franck, issues a report advising against a surprise atomic bombing of Japan. The a report advising against a surprise atomic bombing of Japan. The report states, “If we consider international agreement on total report states, “If we consider international agreement on total prevention of nuclear warfare as the paramount objective…this prevention of nuclear warfare as the paramount objective…this kind of introduction of atomic weapons to the world may easily kind of introduction of atomic weapons to the world may easily destroy all our chances of success.” The report correctly predicts destroy all our chances of success.” The report correctly predicts that dropping an atomic bomb “will mean a flying start toward an that dropping an atomic bomb “will mean a flying start toward an unlimited armaments race.”unlimited armaments race.”

June 14June 14 The Franck Committee Report – with its recommendation that The Franck Committee Report – with its recommendation that

bomb be demonstrated to Japan before being used on civilians – is bomb be demonstrated to Japan before being used on civilians – is taken by Compton to Los Alamos, and copies were given to Fermi, taken by Compton to Los Alamos, and copies were given to Fermi, Lawrence and Oppenheimer. June 16Lawrence and Oppenheimer. June 16

Compton, Fermi, Lawrence and Oppenheimer conclude: “We can Compton, Fermi, Lawrence and Oppenheimer conclude: “We can propose no technical demonstration likely to bring an end to the propose no technical demonstration likely to bring an end to the war; we see no acceptable alternative to direct military use.”war; we see no acceptable alternative to direct military use.”

June 17June 17 McCloy tells Stimson that “there were no more cities to bomb, nMcCloy tells Stimson that “there were no more cities to bomb, n

o more carriers to sink or battleships to shell; we had difficulty fio more carriers to sink or battleships to shell; we had difficulty finding targets.”nding targets.”

June 18June 18 Admiral Leahy makes diary entry noting, “It is my opinion at the Admiral Leahy makes diary entry noting, “It is my opinion at the

present time that a surrender of Japan can be arranged with terpresent time that a surrender of Japan can be arranged with terms that can be accepted by Japan and that will make fully satisfams that can be accepted by Japan and that will make fully satisfactory provision for America’s defense against future trans-Pacifictory provision for America’s defense against future trans-Pacific aggression.” He also notes that General Marshall believes that c aggression.” He also notes that General Marshall believes that an invasion of Kyushu, the southern-most Japanese island, “will an invasion of Kyushu, the southern-most Japanese island, “will not cost us in casualties more than 63,000 of the 190,000 combatnot cost us in casualties more than 63,000 of the 190,000 combatant troops estimated as necessary for the operation.” This may ant troops estimated as necessary for the operation.” This may be compared to later estimates, after the atomic bombings, of 50be compared to later estimates, after the atomic bombings, of 500,000 to 1,000,000 American lives saved.0,000 to 1,000,000 American lives saved.

June 20June 20 A meeting of the Supreme War Direction Council before Emperor A meeting of the Supreme War Direction Council before Emperor

Hirohito is held on the subject of ending the war. According to thHirohito is held on the subject of ending the war. According to the U.S. Strategic Bombing Survey, “the Emperor, supported by the U.S. Strategic Bombing Survey, “the Emperor, supported by the premier, foreign minister and Navy minister, declared for peace;e premier, foreign minister and Navy minister, declared for peace; the army minister and the two chiefs of staff did not concur.” the army minister and the two chiefs of staff did not concur.”

June 26June 26 Stimson, Forrestal and Grew agree that a clarification of surrendStimson, Forrestal and Grew agree that a clarification of surrend

er terms should be issued well before an invasion and with “amer terms should be issued well before an invasion and with “ample time to permit a national reaction to set in.” The three agreple time to permit a national reaction to set in.” The three agreed that “Japan is susceptible to reason.” ed that “Japan is susceptible to reason.”

July 10July 10 At a meeting of the Supreme War Direction Council, Emperor HirAt a meeting of the Supreme War Direction Council, Emperor Hir

ohito urges haste in moves to mediate the peace through Russia.ohito urges haste in moves to mediate the peace through Russia.

July 13July 13 Washington intercepts and decodes a cable from Japanese Washington intercepts and decodes a cable from Japanese

Foreign Minister Shigenori Togo to his Ambassador in Foreign Minister Shigenori Togo to his Ambassador in Moscow that states, “Unconditional surrender is the only Moscow that states, “Unconditional surrender is the only obstacle to peace….”obstacle to peace….”

July 15 July 15 President Truman lands at Antwerp on his way to Potsdam President Truman lands at Antwerp on his way to Potsdam

meeting. Byrnes has convinced him to drop Article 12 of meeting. Byrnes has convinced him to drop Article 12 of the Potsdam Declaration, which had provided assurance the Potsdam Declaration, which had provided assurance that the Emperor would be allowed to retain his throne as a that the Emperor would be allowed to retain his throne as a constitutional monarch. constitutional monarch.

July 16July 16 Trinity test, a plutonium implosion device, takes place at Trinity test, a plutonium implosion device, takes place at

5:29:45 a.m. mountain war time at Alamogordo, New 5:29:45 a.m. mountain war time at Alamogordo, New Mexico. It is the world’s first atomic detonation. Mexico. It is the world’s first atomic detonation.

July 17 July 17 President Truman at Potsdam writes in his diary, “Just spend [sic] a coPresident Truman at Potsdam writes in his diary, “Just spend [sic] a co

uple of hours with Stalin…. He’ll be in the Jap War on August 15th. Finuple of hours with Stalin…. He’ll be in the Jap War on August 15th. Fini Japs when that comes about.”i Japs when that comes about.”

July 21July 21 President Truman approves order for atomic bombs to be usedPresident Truman approves order for atomic bombs to be used July 23July 23 UK Prime Minister Winston Churchill remarks, “[I]t is quite clear that thUK Prime Minister Winston Churchill remarks, “[I]t is quite clear that th

e United States do not at the present time desire Russian participation ie United States do not at the present time desire Russian participation in the war against Japan.”n the war against Japan.”

July 24July 24 Walter Brown, special assistant to Secretary of State Byrnes, writes in hiWalter Brown, special assistant to Secretary of State Byrnes, writes in hi

s journal that Byrnes was now “hoping for time, believing after atomic s journal that Byrnes was now “hoping for time, believing after atomic bomb Japan will surrender and Russia will not get in so much on the kill, bomb Japan will surrender and Russia will not get in so much on the kill, thereby being in a position to press claims against China.”thereby being in a position to press claims against China.”

July 24July 24 Secretary of War Henry Stimson passes on orders for atomic attack.Secretary of War Henry Stimson passes on orders for atomic attack. July 25July 25 General Carl Spatz, commander of the United States Army Strategic Air Forces, reGeneral Carl Spatz, commander of the United States Army Strategic Air Forces, re

ceives the only written order on the use of atomic weapons from acting Chief of Sceives the only written order on the use of atomic weapons from acting Chief of Staff, General Thomas Handy.taff, General Thomas Handy.

July 26 July 26 Potsdam Declaration calls upon Japanese government “to proclaim now the unPotsdam Declaration calls upon Japanese government “to proclaim now the un

conditional surrender of all Japanese armed forces.” The alternative, the Declarconditional surrender of all Japanese armed forces.” The alternative, the Declaration states, is “prompt and utter destruction.”ation states, is “prompt and utter destruction.”

July 26July 26 Forrestal secret diary states, “In the past days Sato in Moscow has been sending Forrestal secret diary states, “In the past days Sato in Moscow has been sending

the strongest language to the Foreign Office at Tokyo his urgent advice for Japan the strongest language to the Foreign Office at Tokyo his urgent advice for Japan to surrender unconditionally. Each time the Foreign Minister, Togo, responds by to surrender unconditionally. Each time the Foreign Minister, Togo, responds by saying that they want Sato to arrange for the Russians to receive Prince Konoye asaying that they want Sato to arrange for the Russians to receive Prince Konoye as a special representative of the Emperor to Moscow. Sato’s persistent reply to ts a special representative of the Emperor to Moscow. Sato’s persistent reply to these messages was that this is a futile hope, that there is no possibility of splitting hese messages was that this is a futile hope, that there is no possibility of splitting the concert of action now existing between Great Britain, the United States and Rthe concert of action now existing between Great Britain, the United States and Russia.”ussia.”

July 28 |July 28 | Japan rejects Potsdam Declaration.Japan rejects Potsdam Declaration. August 6August 6 The world's second atomic bomb, Little Boy, a gun-type uranium The world's second atomic bomb, Little Boy, a gun-type uranium

bomb, is detonated 1,900 feet above Hiroshima, Japan. It has a bomb, is detonated 1,900 feet above Hiroshima, Japan. It has a yield of approximately 15 kilotons TNT. Some 90,000 to 100,000 yield of approximately 15 kilotons TNT. Some 90,000 to 100,000 persons are killed immediately; about 145,000 persons will perish persons are killed immediately; about 145,000 persons will perish from the bombing by the end of 1945.from the bombing by the end of 1945.

August 8August 8 Soviet Union informs Japan that it is entering the war.Soviet Union informs Japan that it is entering the war.

August 9August 9 At 9:44 a.m. Bockscar, a B-29 carrying Fat Man, the world's third atomic At 9:44 a.m. Bockscar, a B-29 carrying Fat Man, the world's third atomic

bomb, arrives at its primary target, Kokura. The city is covered in haze abomb, arrives at its primary target, Kokura. The city is covered in haze and smoke from an American bombing raid on a nearby city. Bockscar turnd smoke from an American bombing raid on a nearby city. Bockscar turns to its secondary target Nagasaki. At 11:02 a.m. the world's third atomns to its secondary target Nagasaki. At 11:02 a.m. the world's third atomic bomb explosion devastates Nagasaki, the intense heat and blast indisic bomb explosion devastates Nagasaki, the intense heat and blast indiscriminately slaughters its inhabitantscriminately slaughters its inhabitants

August 9August 9 President Truman speaks to the American people via radio President Truman speaks to the American people via radio

broadcast He states, “The world will note that the first atomic broadcast He states, “The world will note that the first atomic bomb was dropped on Hiroshima, a military base. That was bomb was dropped on Hiroshima, a military base. That was because we wished in the first instance to avoid, in so far as because we wished in the first instance to avoid, in so far as possible, the killing of civilians.” [The official Bombing Survey possible, the killing of civilians.” [The official Bombing Survey Report stated: “Hiroshima and Nagasaki were chosen as targets Report stated: “Hiroshima and Nagasaki were chosen as targets because of their concentration of activities and population.” More because of their concentration of activities and population.” More than 95 percent of those killed at Hiroshima and Nagasaki were than 95 percent of those killed at Hiroshima and Nagasaki were civilians.]civilians.]

August 9August 9 Atomic bomb dropped on Nagasaki.Atomic bomb dropped on Nagasaki. August 9August 9 Soviet Union begins its offensive against Japan in Manchuria.Soviet Union begins its offensive against Japan in Manchuria. August 14August 14 Japan surrenders.Japan surrenders.

Bibliography:Bibliography: http://www.trumanlibrary.org/teacher/abomb.htmhttp://www.trumanlibrary.org/teacher/abomb.htm www.willamette.edu/cla/wviews/hiroshima.htmlwww.willamette.edu/cla/wviews/hiroshima.html www.socialstudieshelp.com/Lesson_95_Notes.htmwww.socialstudieshelp.com/Lesson_95_Notes.htm www.colorado.edu/AmStudies/lewis/2010/atomic.htmwww.colorado.edu/AmStudies/lewis/2010/atomic.htm History 5N readings, April 12: McGeorge, Berstein, Walzer. History 5N readings, April 12: McGeorge, Berstein, Walzer.

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