Atomic bombings of Hiroshima and Nagasaki
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Atomic bombings of Hiroshima and Nagasaki
Part of the Pacific War, World War II
video
Crew members of the The Great Artiste B-29 bomber which dumped a nuclear bomb to Nagasaki, surrounded the major Charles V. Suinni in Northern Kvinsi, Massachusetts. All crew members participated in historical bombardment. From left to right: sergeant R. Gallagher, Chicago; A staff sergeant. M.Shpitser, Bronx, New York; captain S. D. Olberi, Miami, Florida; captain J. F. Van Pelt Mladshy. Ouk Hill, Western Virginia; F. J. Olivia's lieutenant, Chicago; E.K. Buckley's staff sergeant, Lisbon, Ohio; sergeant of A. T.Degart, Pleynvyyu, Texas and staff sergeant J. D. Kukharek, Columbus, Nebraska.
Two aerial photos of atomic bomb mushroom clouds, over two Japanese cities in 1945.
Atomic bomb mushroom clouds over Hiroshima (left) and Nagasaki (right)
Date August 6 and 9, 1945
Location Hiroshima and Nagasaki, Japan
Result Allied victory
Belligerents
United States
United Kingdom Japan
Commanders and leaders
United States William S. Parsons
United States Paul W. Tibbets, Jr. Empire of Japan Shunroku Hata
Units involved
Manhattan District: 50 U.S., 2 British
509th Composite Group: 1,770 U.S. Second General Army: Hiroshima: 40,000
Nagasaki: 9,000
Casualties and losses
20 U.S., Dutch, British prisoners of war killed 90,000–166,000 killed in Hiroshima
39,000–80,000 killed in Nagasaki
Total: 129,000–246,000+ killed
[show] v t e
Pacific War
The atomic bombings of the cities of Hiroshima and Nagasaki in Japan were conducted by the United States during the final stages of World War II in August 1945. The two bombings were the first and remain the only use of nuclear weapons in warfare.
Following a firebombing campaign that destroyed many Japanese cities, the Allies prepared for a costly invasion of Japan. The war in Europe ended when Nazi Germany signed its instrument of surrender on May 8, 1945, but the Pacific War continued. Together with the United Kingdom and China, the United States called for the unconditional surrender of the Japanese armed forces in the Potsdam Declaration on July 26, 1945, threatening "prompt and utter destruction".
By August 1945, the Allied Manhattan Project had successfully tested an atomic device and had produced weapons based on two alternate designs. The 509th Composite Group of the U.S. Army Air Forces was equipped with a Silverplate Boeing B-29 Superfortress that could deliver them from Tinian in the Mariana Islands. A uranium gun-type atomic bomb (Little Boy) was dropped on Hiroshima on August 6, 1945, followed by a plutonium implosion-type bomb (Fat Man) on the city of Nagasaki on August 9. Within the first two to four months of the bombings, the acute effects killed 90,000–166,000 people in Hiroshima and 60,000–80,000 in Nagasaki; roughly half of the deaths in each city occurred on the first day. During the following months, large numbers died from the effect of burns, radiation sickness, and other injuries, compounded by illness. In both cities, most of the dead were civilians, although Hiroshima had a sizeable garrison.
On August 15, just days after the bombing of Nagasaki and the Soviet Union's declaration of war, Japan announced its surrender to the Allies. On September 2, it signed the instrument of surrender, ending World War II. The bombings' role in Japan's surrender and their ethical justification are still debated.
Pacific War
Main article: Pacific War
A map of East Asia and the Western Pacific during World War II
Situation of Pacific War by August 1, 1945. Japan still had control of all of Manchuria, Korea, Taiwan and Indochina, a large part of China, including most of the main Chinese cities, and much of the Dutch East Indies
In 1945, the Pacific War between the Empire of Japan and the Allies entered its fourth year. Of the 1.25 million battle casualties incurred by the United States in World War II, including both military personnel killed in action and wounded in action, nearly one million occurred in the twelve-month period from June 1944 to June 1945. December 1944 saw American battle casualties hit an all-time monthly high of 88,000 as a result of the German Ardennes Offensive.[1] In the Pacific the Allies returned to the Philippines,[2] recaptured Burma,[3] and invaded Borneo.[4] Offensives were undertaken to reduce the Japanese forces remaining in Bougainville, New Guinea and the Philippines.[5] In April 1945, American forces landed on Okinawa, where heavy fighting continued until June. Along the way, the ratio of Japanese to American casualties dropped from 5:1 in the Philippines to 2:1 on Okinawa.[1]
As the Allied advance moved inexorably towards Japan, conditions became steadily worse for the Japanese people. Japan's merchant fleet declined from 5,250,000 gross tons in 1941 to 1,560,000 tons in March 1945, and 557,000 tons in August 1945. Lack of raw materials forced the Japanese war economy into a steep decline after the middle of 1944. The civilian economy, which had slowly deteriorated throughout the war, reached disastrous levels by the middle of 1945. The loss of shipping also affected the fishing fleet, and the 1945 catch was only 22% of that in 1941. The 1945 rice harvest was the worst since 1909, and hunger and malnutrition became widespread. In February 1945, Prince Fumimaro Konoe advised the Emperor Hirohito that defeat was inevitable, and urged him to abdicate.[6]
Preparations to invade Japan
Main article: Operation Downfall
Even before the surrender of Nazi Germany on May 8, 1945, plans were underway for the largest operation of the Pacific War, Operation Downfall, the invasion of Japan.[7] The operation had two parts: Operations Olympic and Coronet. Set to begin in October 1945, Olympic involved a series of landings by the U.S. Sixth Army intended to capture the southern third of the southernmost main Japanese island, Kyūshū.[8] Operation Olympic was to be followed in March 1946 by Operation Coronet, the capture of the Kantō Plain, near Tokyo on the main Japanese island of Honshū by the U.S. First, Eighth and Tenth Armies. The target date was chosen to allow for Olympic to complete its objectives, for troops to be redeployed from Europe, and the Japanese winter to pass.[9]
Uncle Sam holding a spanner, rolling up his sleeves
U.S. Army poster prepares the public for the invasion of Japan after ending war on Germany and Italy
Japan's geography made this invasion plan obvious to the Japanese; they were able to predict the Allied invasion plans accurately and thus adjust their defensive plan, Operation Ketsugō, accordingly. The Japanese planned an all-out defense of Kyūshū, with little left in reserve for any subsequent defense operations.[10] Four veteran divisions were withdrawn from the Kwantung Army in Manchuria in March 1945 to strengthen the forces in Japan,[11] and 45 new divisions were activated between February and May 1945. Most were immobile formations for coastal defense, but 16 were high quality mobile divisions.[12] In all, there were 2.3 million Japanese Army troops prepared to defend the home islands, backed by a civilian militia of 28 million men and women. Casualty predictions varied widely, but were extremely high. The Vice Chief of the Imperial Japanese Navy General Staff, Vice Admiral Takijirō Ōnishi, predicted up to 20 million Japanese deaths.[13]
A study from June 15, 1945, by the Joint War Plans Committee,[14] who provided planning information to the Joint Chiefs of Staff, estimated that Olympic would result in between 130,000 and 220,000 U.S. casualties of which U.S. dead would be the range from 25,000 to 46,000. Delivered on June 15, 1945, after insight gained from the Battle of Okinawa, the study noted Japan's inadequate defenses due to the very effective sea blockade and the American firebombing campaign. The Chief of Staff of the United States Army, General of the Army George Marshall, and the Army Commander in Chief in the Pacific, General of the Army Douglas MacArthur, signed documents agreeing with the Joint War Plans Committee estimate.[15]
The Americans were alarmed by the Japanese buildup, which was accurately tracked through Ultra intelligence.[16] Secretary of War Henry L. Stimson was sufficiently concerned about high American estimates of probable casualties to commission his own study by Quincy Wright and William Shockley. Wright and Shockley spoke with Colonels James McCormack and Dean Rusk, and examined casualty forecasts by Michael E. DeBakey and Gilbert Beebe. Wright and Shockley estimated the invading Allies would suffer between 1.7 and 4 million casualties in such a scenario, of whom between 400,000 and 800,000 would be dead, while Japanese casualties would have been around 5 to 10 million.[17][18]
Marshall began contemplating the use of a weapon which was "readily available and which assuredly can decrease the cost in American lives":[19] poison gas. Quantities of phosgene, mustard gas, tear gas and cyanogen chloride were moved to Luzon from stockpiles in Australia and New Guinea in preparation for Operation Olympic, and MacArthur ensured that Chemical Warfare Service units were trained in their use.[19] Consideration was also given to using biological weapons against Japan.[20]
Air raids on Japan
Main article: Air raids on Japan
Black and white photo of a four engined World War II-era aircraft being viewed from above while it is flying over a city. A large cloud of smoke is visible immediately below the aircraft.
A B-29 over Osaka on June 1, 1945
While the United States had developed plans for an air campaign against Japan prior to the Pacific War, the capture of Allied bases in the western Pacific in the first weeks of the conflict meant that this offensive did not begin until mid-1944 when the long-ranged Boeing B-29 Superfortress became ready for use in combat.[21] Operation Matterhorn involved India-based B-29s staging through bases around Chengdu in China to make a series of raids on strategic targets in Japan.[22] It had failed to achieve the strategic objectives that the planners had intended, largely because of logistical problems, the bomber's mechanical difficulties, the vulnerability of Chinese staging bases, and the extreme range required to reach key Japanese cities.[23]
United States Army Air Forces (USAAF) Brigadier General Haywood S. Hansell determined that Guam, Tinian, and Saipan in the Mariana Islands would better serve as B-29 bases, but they were in Japanese hands.[24] Strategies were shifted to accommodate the air war,[25] and the islands were captured between June and August 1944. Air bases were developed,[26] and B-29 operations commenced from the Marianas in October 1944.[27] These bases were easily resupplied by cargo ships.[28] The XXI Bomber Command began missions against Japan on November 18, 1944.[29]
The early attempts to bomb Japan from the Marianas proved just as ineffective as the China-based B-29s had been. Hansell continued the practice of conducting so-called high-altitude precision bombing even after these tactics had not produced acceptable results.[30] These efforts proved unsuccessful due to logistical difficulties with the remote location, technical problems with the new and advanced aircraft, unfavorable weather conditions, and enemy action.[31][32]
A vast devastated area with only a few burned out buildings standing
The Operation Meetinghouse firebombing of Tokyo on the night of March 9–10, 1945, was the single deadliest air raid of World War II;[33] with a greater area of fire damage and loss of life than the nuclear bombings of Hiroshima or Nagasaki as single events.[34][35]
Hansell's successor, Major General Curtis LeMay, assumed command in January 1945 and initially continued to use the same tactics, with equally unsatisfactory results. Under pressure from USAAF headquarters in Washington, LeMay changed tactics and decided that low-level incendiary raids against Japanese cities were the only way to destroy their production capabilities, shifting from precision bombing to area bombardment with incendiaries.[36] The attacks initially targeted key industrial facilities but from March 1945, they were frequently directed against urban areas. Much of the manufacturing process was carried out in small workshops and private homes.[37]
Like most strategic bombing during World War II, the aim of the USAAF offensive against Japan was to destroy the enemy's war industries, kill or disable civilian employees of these industries, and undermine civilian morale. Civilians who took part in the war effort through such activities as building fortifications and manufacturing munitions and other war materials in factories and workshops were considered combatants in a legal sense and therefore liable to be attacked.[38][39]
Over the next six months, the XXI Bomber Command under LeMay firebombed 67 Japanese cities. The firebombing of Tokyo, codenamed Operation Meetinghouse, on March 9–10 killed an estimated 100,000 people and destroyed 16 square miles (41 km2) of the city and 267,000 buildings in a single night—the deadliest bombing raid of the war—at a cost of 20 B-29s shot down by flak and fighters.[40] By mid-June, Japan's six largest cities had been devastated.[41] The end of the fighting on Okinawa that month provided airfields even closer to the Japanese mainland, allowing the bombing campaign to be further escalated. Aircraft flying from Allied aircraft carriers and the Ryukyu Islands also regularly struck targets in Japan during 1945 in preparation for Operation Downfall.[42] Firebombing switched to smaller cities, with populations ranging from 60,000 to 350,000. These raids were also very successful.[43]
The Japanese military was unable to stop the Allied attacks and the country's civil defense preparations proved inadequate. Japanese fighters and antiaircraft guns had difficulty engaging bombers flying at high altitude.[44] From April 1945, the Japanese interceptors also had to face American fighter escorts based on Iwo Jima and Okinawa.[45] That month, the Imperial Japanese Army Air Service and Imperial Japanese Navy Air Service stopped attempting to intercept the air raids in order to preserve fighter aircraft to counter the expected invasion.[46] By mid-1945 the Japanese only occasionally scrambled aircraft to intercept individual B-29s conducting reconnaissance sorties over the country, in order to conserve supplies of fuel.[47] By July 1945, the Japanese had stockpiled 1,156,000 US barrels (137,800,000 l; 36,400,000 US gal; 30,300,000 imp gal) of avgas for the invasion of Japan.[48] While the Japanese military decided to resume attacks on Allied bombers from late June, by this time there were too few operational fighters available for this change of tactics to hinder the Allied air raids.[49]
Atomic bomb development
Main article: Manhattan Project
Working in collaboration with the United Kingdom and Canada, with their respective projects Tube Alloys and Chalk River Laboratories,[50][51] the Manhattan Project, under the direction of Major General Leslie R. Groves, Jr., of the U.S. Army Corps of Engineers, designed and built the first atomic bombs.[52] Preliminary research began in 1939, originally in fear that the German atomic bomb project would develop atomic weapons first.[53] With the defeat of Germany in May 1945, plans shifted to using the bomb against Japan.[54]
Two types of bombs were eventually devised by scientists and technicians at Los Alamos under the leadership of American physicist J. Robert Oppenheimer. The Hiroshima bomb, known as a Little Boy, was a gun-type fission weapon that used uranium-235, a rare isotope of uranium extracted in giant factories at Oak Ridge, Tennessee.[55] The other was a more powerful and efficient but more complicated implosion-type nuclear weapon using plutonium-239, a synthetic element created in nuclear reactors at Hanford, Washington. A test implosion weapon, the gadget, was detonated at Trinity Site, on July 16, 1945, near Alamogordo, New Mexico.[56] The Nagasaki bomb, a Fat Man, was a similar device.[57]
There was a Japanese nuclear weapon program, but it lacked the human, mineral and financial resources of the Manhattan Project, and never made much progress towards developing an atomic bomb.[58]
Preparations
Organization and training
Color photo of three silver four engined World War II-era aircraft neatly lined up alongside a runway
Aircraft of the 509th Composite Group that took part in the Hiroshima bombing. Left to right: backup plane, The Great Artiste, Enola Gay
The 509th Composite Group was constituted on December 9, 1944, and activated on December 17, 1944, at Wendover Army Air Field, Utah, commanded by Colonel Paul Tibbets.[59] Tibbets was assigned to organize and command a combat group to develop the means of delivering an atomic weapon against targets in Germany and Japan. Because the flying squadrons of the group consisted of both bomber and transport aircraft, the group was designated as a "composite" rather than a "bombardment" unit.[60]
Working with the Manhattan Project at Los Alamos, Tibbets selected Wendover for his training base over Great Bend, Kansas, and Mountain Home, Idaho, because of its remoteness.[61] Each bombardier completed at least 50 practice drops of inert pumpkin bombs and Tibbets declared his group combat-ready.[62]
Three men in military fatigues, without jackets or ties.
The "Tinian Joint Chiefs": Captain William S. Parsons (left), Rear Admiral William R. Purnell (center), and Brigadier General Thomas F. Farrell (right)
The 509th Composite Group had an authorized strength of 225 officers and 1,542 enlisted men, almost all of whom eventually deployed to Tinian. In addition to its authorized strength, the 509th had attached to it on Tinian 51 civilian and military personnel from Project Alberta,[63] known as the 1st Technical Detachment.[64] The 509th Composite Group's 393d Bombardment Squadron was equipped with 15 Silverplate B-29s. These aircraft were specially adapted to carry nuclear weapons, and were equipped with fuel-injected engines, Curtiss Electric reversible-pitch propellers, pneumatic actuators for rapid opening and closing of bomb bay doors and other improvements.[65]
The ground support echelon of the 509th Composite Group moved by rail on April 26, 1945, to its port of embarkation at Seattle, Washington. On May 6 the support elements sailed on the SS Cape Victory for the Marianas, while group materiel was shipped on the SS Emile Berliner. The Cape Victory made brief port calls at Honolulu and Eniwetok but the passengers were not permitted to leave the dock area. An advance party of the air echelon, consisting of 29 officers and 61 enlisted men flew by C-54 to North Field on Tinian, between May 15 and 22.[66]
There were also two representatives from Washington, D.C., Brigadier General Thomas Farrell, the deputy commander of the Manhattan Project, and Rear Admiral William R. Purnell of the Military Policy Committee,[67] who were on hand to decide higher policy matters on the spot. Along with Captain William S. Parsons, the commander of Project Alberta, they became known as the "Tinian Joint Chiefs".[68]
Choice of targets
map of Japan and the Marianas Islands indicating the routes taken by the raids. One goes straight to Iwo Jima and Hiroshima and back the same way. The other goes to the southern tip of Japan, up to Kokura, down to Nagasaki, and the southwest to Okinawa befofore heading back to Tinian.
The mission runs of August 6 and August 9, with Hiroshima, Nagasaki, and Kokura (the original target for August 9) displayed.
General Thomas Handy's order to General Carl Spaatz authorizing the dropping of the atomic bombs
In April 1945, Marshall asked Groves to nominate specific targets for bombing for final approval by himself and Stimson. Groves formed a Target Committee chaired by himself, that included Farrell, Major John A. Derry, Colonel William P. Fisher, Joyce C. Stearns and David M. Dennison from the USAAF; and scientists John von Neumann, Robert R. Wilson and William Penney from the Manhattan Project. The Target Committee met in Washington on April 27; at Los Alamos on May 10, where it was able to talk to the scientists and technicians there; and finally in Washington on May 28, where it was briefed by Tibbets and Commander Frederick Ashworth from Project Alberta, and the Manhattan Project's scientific advisor, Richard C. Tolman.[69]
The Target Committee nominated five targets: Kokura, the site of one of Japan's largest munitions plants; Hiroshima, an embarkation port and industrial center that was the site of a major military headquarters; Yokohama, an urban center for aircraft manufacture, machine tools, docks, electrical equipment and oil refineries; Niigata, a port with industrial facilities including steel and aluminum plants and an oil refinery; and Kyoto, a major industrial center. The target selection was subject to the following criteria:
The target was larger than 3 mi (4.8 km) in diameter and was an important target in a large urban area.
The blast would create effective damage.
The target was unlikely to be attacked by August 1945.[70]
These cities were largely untouched during the nightly bombing raids and the Army Air Forces agreed to leave them off the target list so accurate assessment of the weapon could be made. Hiroshima was described as "an important army depot and port of embarkation in the middle of an urban industrial area. It is a good radar target and it is such a size that a large part of the city could be extensively damaged. There are adjacent hills which are likely to produce a focusing effect which would considerably increase the blast damage. Due to rivers it is not a good incendiary target."[70]
The Target Committee stated that "It was agreed that psychological factors in the target selection were of great importance. Two aspects of this are (1) obtaining the greatest psychological effect against Japan and (2) making the initial use sufficiently spectacular for the importance of the weapon to be internationally recognized when publicity on it is released. Kyoto had the advantage of being an important center for military industry, as well an intellectual center and hence a population better able to appreciate the significance of the weapon. The Emperor's palace in Tokyo has a greater fame than any other target but is of least strategic value."[70]
Edwin O. Reischauer, a Japan expert for the U.S. Army Intelligence Service, was incorrectly said to have prevented the bombing of Kyoto.[70] In his autobiography, Reischauer specifically refuted this claim:
... the only person deserving credit for saving Kyoto from destruction is Henry L. Stimson, the Secretary of War at the time, who had known and admired Kyoto ever since his honeymoon there several decades earlier.[71]
On May 30, Stimson asked Groves to remove Kyoto from the target list, but Groves pointed to its military and industrial significance.[72] Stimson then approached President Harry S. Truman about the matter. Truman agreed with Stimson, and Kyoto was temporarily removed from the target list.[73] Groves attempted to restore Kyoto to the target list in July, but Stimson remained adamant.[74][75] On July 25, Nagasaki was put on the target list in place of Kyoto.[75] Orders for the attack were issued to General Carl Spaatz on July 25 under the signature of General Thomas T. Handy, the acting Chief of Staff, since Marshall was at the Potsdam Conference with Truman.[76] That day, Truman noted in his diary that:
This weapon is to be used against Japan between now and August 10th. I have told the Sec. of War, Mr. Stimson, to use it so that military objectives and soldiers and sailors are the target and not women and children. Even if the Japs are savages, ruthless, merciless and fanatic, we as the leader of the world for the common welfare cannot drop that terrible bomb on the old capital [Kyoto] or the new [Tokyo]. He and I are in accord. The target will be a purely military one.[77]
Proposed demonstration
In early May 1945, the Interim Committee was created by Stimson at the urging of leaders of the Manhattan Project and with the approval of Truman to advise on matters pertaining to nuclear energy.[78] During the meetings on May 31 and June 1, scientist Ernest Lawrence had suggested giving the Japanese a non-combat demonstration.[79] Arthur Compton later recalled that:
It was evident that everyone would suspect trickery. If a bomb were exploded in Japan with previous notice, the Japanese air power was still adequate to give serious interference. An atomic bomb was an intricate device, still in the developmental stage. Its operation would be far from routine. If during the final adjustments of the bomb the Japanese defenders should attack, a faulty move might easily result in some kind of failure. Such an end to an advertised demonstration of power would be much worse that if the attempt had not been made. It was now evident that when the time came for the bombs to be used we should have only one of them available, followed afterwards by others at all-too-long intervals. We could not afford the chance that one of them might be a dud. If the test were made on some neutral territory, it was hard to believe that Japan's determined and fanatical military men would be impressed. If such an open test were made first and failed to bring surrender, the chance would be gone to give the shock of surprise that proved so effective. On the contrary, it would make the Japanese ready to interfere with an atomic attack if they could. Though the possibility of a demonstration that would not destroy human lives was attractive, no one could suggest a way in which it could be made so convincing that it would be likely to stop the war.[80]
The possibility of a demonstration was raised again in the Franck Report issued by physicist James Franck on June 11 and the Scientific Advisory Panel rejected his report on June 16, saying that "we can propose no technical demonstration likely to bring an end to the war; we see no acceptable alternative to direct military use." Franck then took the report to Washington, D.C., where the Interim Committee met on June 21 to re-examine its earlier conclusions; but it reaffirmed that there was no alternative to the use of the bomb on a military target.[81]
Like Compton, many U.S. officials and scientists argued that a demonstration would sacrifice the shock value of the atomic attack, and the Japanese could deny the atomic bomb was lethal, making the mission less likely to produce surrender. Allied prisoners of war might be moved to the demonstration site and be killed by the bomb. They also worried that the bomb might be a dud since the Trinity test was of a stationary device, not an air-dropped bomb. In addition, only two bombs would be available at the start of August, although more were in production, and they cost billions of dollars, so using one for a demonstration would be expensive.[82][83]
Leaflets
B-29s dropping bombs. There are twelve circles with Japanese writing in them.
This type of leaflet was dropped on Japan, showing the names of 12 Japanese cities targeted for destruction by firebombing. The other side contained text saying "we cannot promise that only these cities will be among those attacked ..."
For several months, the U.S. had dropped more than 63 million leaflets across Japan warning civilians of air raids. Many Japanese cities suffered terrible damage from aerial bombings, some were as much as 97% destroyed. LeMay thought that this would increase the psychological impact of bombing, and reduce the stigma of area bombing cities. Even with the warnings, Japanese opposition to the war remained ineffective. In general, the Japanese regarded the leaflet messages as truthful, but anyone who was caught in possession of one was arrested.[84][85] Leaflet texts were prepared by recent Japanese prisoners of war because they were thought to be the best choice "to appeal to their compatriots".[86]
In preparation for dropping an atomic bomb on Hiroshima, U.S. military leaders decided against a demonstration bomb, and against a special leaflet warning, in both cases because of the uncertainty of a successful detonation, and the wish to maximize psychological shock.[87] No warning was given to Hiroshima that a new and much more destructive bomb was going to be dropped.[88] Various sources give conflicting information about when the last leaflets were dropped on Hiroshima prior to the atomic bomb. Robert Jay Lifton writes that it was July 27,[88] and Theodore H. McNelly that it was July 3.[87] The USAAF history notes eleven cities were targeted with leaflets on July 27, but Hiroshima was not one of them, and there were no leaflet sorties on July 30.[85] Leaflet sorties were undertaken on August 1 and 4. It is very likely that Hiroshima was leafleted in late July or early August, as survivor accounts talk about a delivery of leaflets a few days before the atomic bomb was dropped.[88] One such leaflet lists twelve cities targeted for firebombing: Otaru, Akita, Hachinohe, Fukushima, Urawa, Takayama, Iwakuni, Tottori, Imabari, Yawata, Miyakonojo, and Saga. Hiroshima was not listed.[89][90][91][92]
Potsdam ultimatum
On July 26, Allied leaders issued the Potsdam Declaration outlining terms of surrender for Japan. It was presented as an ultimatum and stated that without a surrender, the Allies would attack Japan, resulting in "the inevitable and complete destruction of the Japanese armed forces and just as inevitably the utter devastation of the Japanese homeland". The atomic bomb was not mentioned in the communiqué. On July 28, Japanese papers reported that the declaration had been rejected by the Japanese government. That afternoon, Prime Minister Suzuki Kantarō declared at a press conference that the Potsdam Declaration was no more than a rehash (yakinaoshi) of the Cairo Declaration and that the government intended to ignore it (mokusatsu, "kill by silence").[93] The statement was taken by both Japanese and foreign papers as a clear rejection of the declaration. Emperor Hirohito, who was waiting for a Soviet reply to non-committal Japanese peace feelers, made no move to change the government position.[94]
Under the 1943 Quebec Agreement with the United Kingdom, the United States had agreed that nuclear weapons would not be used against another country without mutual consent. In June 1945 the head of the British Joint Staff Mission, Field Marshal Sir Henry Maitland Wilson, agreed that the use of nuclear weapons against Japan would be officially recorded as a decision of the Combined Policy Committee.[95] At Potsdam, Truman agreed to a request from Winston Churchill that Britain be represented when the atomic bomb was dropped. William Penney and Group Captain Leonard Cheshire were sent to Tinian, but found that LeMay would not let them accompany the mission. All they could do was send a strongly worded signal back to Wilson.[96]
Bombs
The Little Boy bomb, except for the uranium payload, was ready at the beginning of May 1945.[97] The uranium-235 projectile was completed on June 15, and the target on July 24.[98] The target and bomb pre-assemblies (partly assembled bombs without the fissile components) left Hunters Point Naval Shipyard, California, on July 16 aboard the cruiser USS Indianapolis, arriving July 26.[99] The target inserts followed by air on July 30.[98]
The first plutonium core, along with its polonium-beryllium urchin initiator, was transported in the custody of Project Alberta courier Raemer Schreiber in a magnesium field carrying case designed for the purpose by Philip Morrison. Magnesium was chosen because it does not act as a tamper.[100] The core departed from Kirtland Army Air Field on a C-54 transport aircraft of the 509th Composite Group's 320th Troop Carrier Squadron on July 26, and arrived at North Field July 28. Three Fat Man high-explosive pre-assemblies, designated F31, F32, and F33, were picked up at Kirtland on July 28 by three B-29s, from the 393d Bombardment Squadron, plus one from the 216th Army Air Force Base Unit, and transported to North Field, arriving on August 2.[101]
Hiroshima
Hiroshima during World War II
A Silver aircraft with "Enola Gay" and "82" painted on the nose. Seven men stand in front of it. Four are wearing shorts, four are wearing t shirts, and the only ones with hats have baseball caps. Tibbets is distinctively wearing correct uniform.
The Enola Gay dropped the "Little Boy" atomic bomb on Hiroshima. In this photograph are five of the aircraft's ground crew with mission commander Paul Tibbets in the center.
At the time of its bombing, Hiroshima was a city of both industrial and military significance. A number of military units were located nearby, the most important of which was the headquarters of Field Marshal Shunroku Hata's Second General Army, which commanded the defense of all of southern Japan,[102] and was located in Hiroshima Castle. Hata's command consisted of some 400,000 men, most of whom were on Kyushu where an Allied invasion was correctly anticipated.[103] Also present in Hiroshima were the headquarters of the 59th Army, the 5th Division and the 224th Division, a recently formed mobile unit.[104] The city was defended by five batteries of 7-and-8-centimeter (2.8 and 3.1 in) anti-aircraft guns of the 3rd Anti-Aircraft Division, including units from the 121st and 122nd Anti-Aircraft Regiments and the 22nd and 45th Separate Anti-Aircraft Battalions. In total, over 40,000 military personnel were stationed in the city.[105]
Hiroshima was a minor supply and logistics base for the Japanese military, but it also had large stockpiles of military supplies.[106] The city was a communications center, a key port for shipping and an assembly area for troops.[72] It was also the second largest city in Japan after Kyoto that was still undamaged by air raids,[107] due to the fact that it lacked the aircraft manufacturing industry that was the XXI Bomber Command's priority target. On July 3, the Joint Chiefs of Staff placed it off limits to bombers, along with Kokura, Niigata and Kyoto.[108]
The center of the city contained several reinforced concrete buildings and lighter structures. Outside the center, the area was congested by a dense collection of small wooden workshops set among Japanese houses. A few larger industrial plants lay near the outskirts of the city. The houses were constructed of wood with tile roofs, and many of the industrial buildings were also built around wood frames. The city as a whole was highly susceptible to fire damage.[109]
The population of Hiroshima had reached a peak of over 381,000 earlier in the war but prior to the atomic bombing, the population had steadily decreased because of a systematic evacuation ordered by the Japanese government. At the time of the attack, the population was approximately 340,000–350,000.[110] Residents wondered why Hiroshima had been spared destruction by firebombing.[111] Some speculated that the city was to be saved for U.S. occupation headquarters, others thought perhaps their relatives in Hawaii and California had petitioned the U.S. government to avoid bombing Hiroshima.[112] More realistic city officials had ordered buildings torn down to create long, straight firebreaks, beginning in 1944.[113] Firebreaks continued to be expanded and extended up to the morning of August 6, 1945.[114]
The bombing
Hiroshima was the primary target of the first nuclear bombing mission on 6 August, with Kokura and Nagasaki as alternative targets. The 393d Bombardment Squadron B-29 Enola Gay, piloted by Tibbets, took off from North Field, Tinian, about six hours' flight time from Japan. The Enola Gay (named after Tibbets' mother) was accompanied by two other B-29s. The Great Artiste, commanded by Major Charles Sweeney, carried instrumentation, and a then-nameless aircraft later called Necessary Evil, commanded by Captain George Marquardt, served as the photography aircraft.[115]
A mushroom cloud forming.
Seizo Yamada's ground level photo taken approximately 7 km (4.3 mi) northeast of Hiroshima
Another view of the mushroom cloud forming, from further away.
Picture found in Honkawa Elementary School in 2013 of the Hiroshima atom bomb cloud, believed to have been taken about 30 minutes after detonation from about 10 km (6.2 mi) east of the hypocenter
Special Mission 13, Primary target Hiroshima, August 6, 1945[115][116]
Aircraft Pilot Call Sign Mission role
Straight Flush Major Claude R. Eatherly Dimples 85 Weather reconnaissance (Hiroshima)
Jabit III Major John A. Wilson Dimples 71 Weather reconnaissance (Kokura)
Full House Major Ralph R. Taylor Dimples 83 Weather reconnaissance (Nagasaki)
Enola Gay Colonel Paul W. Tibbets Dimples 82 Weapon Delivery
The Great Artiste Major Charles W. Sweeney Dimples 89 Blast measurement instrumentation
Necessary Evil Captain. George W. Marquardt Dimples 91 Strike observation and photography
Top Secret Captain Charles F. McKnight Dimples 72 Strike spare—did not complete mission
After leaving Tinian the aircraft made their way separately to Iwo Jima to rendezvous with Sweeney and Marquardt at 05:55 at 9,200 feet (2,800 m),[117] and set course for Japan. The aircraft arrived over the target in clear visibility at 31,060 feet (9,470 m).[118] Parsons, who was in command of the mission, armed the bomb during the flight to minimize the risks during takeoff. He had witnessed four B-29s crash and burn at takeoff, and feared that a nuclear explosion would occur if a B-29 crashed with an armed Little Boy on board.[119] His assistant, Second Lieutenant Morris R. Jeppson, removed the safety devices 30 minutes before reaching the target area.[120]
During the night of August 5–6, Japanese early warning radar detected the approach of numerous American aircraft headed for the southern part of Japan. Radar detected 65 bombers headed for Saga, 102 bound for Maebashi, 261 en route to Nishinomiya, 111 headed for Ube and 66 bound for Imabari. An alert was given and radio broadcasting stopped in many cities, among them Hiroshima. The all-clear was sounded in Hiroshima at 00:05.[121] About an hour before the bombing, the air raid alert was sounded again, as Straight Flush flew over the city. It broadcast a short message which was picked up by Enola Gay. It read: "Cloud cover less than 3/10th at all altitudes. Advice: bomb primary."[122] The all-clear was sounded over Hiroshima again at 07:09.[123]
At 08:09 Tibbets started his bomb run and handed control over to his bombardier, Major Thomas Ferebee.[124] The release at 08:15 (Hiroshima time) went as planned, and the Little Boy containing about 64 kg (141 lb) of uranium-235 took 44.4 seconds to fall from the aircraft flying at about 31,000 feet (9,400 m) to a detonation height of about 1,900 feet (580 m) above the city.[125][126][127] Enola Gay traveled 11.5 mi (18.5 km) before it felt the shock waves from the blast.[128]
Due to crosswind, the bomb missed the aiming point, the Aioi Bridge, by approximately 800 ft (240 m) and detonated directly over Shima Surgical Clinic[129] at 34.39468°N 132.45462°E. It created a blast equivalent to 16 kilotons of TNT (67 TJ), ± 2 kt.[126] The weapon was considered very inefficient, with only 1.7% of its material fissioning.[130] The radius of total destruction was about 1 mile (1.6 km), with resulting fires across 4.4 square miles (11 km2).[131]
People on the ground reported seeing a pika or brilliant flash of light followed by a don, a loud booming sound.[132] Some 70,000–80,000 people, of whom 20,000 were soldiers, or around 30% of the population of Hiroshima, were killed by the blast and resultant firestorm,[133][134] and another 70,000 injured.[135]
Events on the ground
Some of the reinforced concrete buildings in Hiroshima had been very strongly constructed because of the earthquake danger in Japan, and their framework did not collapse even though they were fairly close to the blast center. Since the bomb detonated in the air, the blast was directed more downward than sideways, which was largely responsible for the survival of the Prefectural Industrial Promotional Hall, now commonly known as the Genbaku (A-bomb) dome. This building was designed and built by the Czech architect Jan Letzel, and was only 150 m (490 ft) from ground zero. The ruin was named Hiroshima Peace Memorial and was made a UNESCO World Heritage Site in 1996 over the objections of the United States and China, which expressed reservations on the grounds that other Asian nations were the ones who suffered the greatest loss of life and property, and a focus on Japan lacked historical perspective.[136]
The Americans estimated that 4.7 square miles (12 km2) of the city were destroyed. Japanese officials determined that 69% of Hiroshima's buildings were destroyed and another 6–7% damaged.[137] The bombing started fires that spread rapidly through wood and paper homes. As in other Japanese cities, the firebreaks proved ineffective.[138]
Hiroshima bombing
Hiroshima aftermath
Strike order for the Hiroshima bombing as posted on August 5, 1945
Injured civilian casualties
The Hiroshima Genbaku Dome after the bombing
The dark portions of the garments this victim wore during the flash caused burns on the skin
Eizō Nomura was the closest known survivor, who was in the basement of a reinforced concrete building (it remained as the Rest House after the war) only 170 metres (560 ft) from ground zero (the hypocenter) at the time of the attack.[139][140] He lived into his 80s.[141][142] Akiko Takakura was among the closest survivors to the hypocenter of the blast. She had been in the solidly-built Bank of Hiroshima only 300 meters (980 ft) from ground-zero at the time of the attack.[143]
Over 90% of the doctors and 93% of the nurses in Hiroshima were killed or injured—most had been in the downtown area which received the greatest damage.[144] The hospitals were destroyed or heavily damaged. Only one doctor, Terufumi Sasaki, remained on duty at the Red Cross Hospital.[138] Nonetheless, by early afternoon, the police and volunteers had established evacuation centres at hospitals, schools and tram stations, and a morgue was established in the Asano library.[145]
Most elements of the Japanese Second General Army headquarters were at physical training on the grounds of Hiroshima Castle, barely 900 yards (820 m) from the hypocenter. The attack killed 3,243 troops on the parade ground.[146] The communications room of Chugoku Military District Headquarters that was responsible for issuing and lifting air raid warnings was in a semi-basement in the castle. Yoshie Oka, a Hijiyama Girls High School student who had been mobilized to serve as a communications officer had just sent a message that the alarm had been issued for Hiroshima and Yamaguchi when the bomb exploded. She used a special phone to inform Fukuyama Headquarters that "Hiroshima has been attacked by a new type of bomb. The city is in a state of near-total destruction."[147]
Since Mayor Senkichi Awaya had been killed while eating breakfast with his son and granddaughter at the mayoral residence, Field Marshal Hata, who was only slightly wounded, took over the administration of the city, and coordinated relief efforts. Many of his staff had been killed or fatally wounded, including a Korean prince of the Joseon Dynasty, Yi Wu, who was serving as a lieutenant colonel in the Japanese Army.[148][149] Hata's senior surviving staff officer was the wounded Colonel Kumao Imoto, who acted as his chief of staff. Hiroshima Ujina Harbor was undamaged, and soldiers from there used suicide boats intended to repel the American invasion to collect the wounded, and take them down the rivers to the military hospital at Ujina.[148] Trucks and trains brought in relief supplies and evacuated survivors from the city.[150]
Twelve American airmen were imprisoned at the Chugoku Military Police Headquarters located about 1,300 feet (400 m) from the hypocenter of the blast.[151] Most died instantly, although two were reported to have been executed by their captors, and two prisoners badly injured by the bombing were left next the Aioi Bridge by the Kempei Tai, where they were stoned to death.[152]
Japanese realization of the bombing
Hiroshima before the bombing.
Hiroshima after the bombing.
The Tokyo control operator of the Japan Broadcasting Corporation noticed that the Hiroshima station had gone off the air. He tried to re-establish his program by using another telephone line, but it too had failed.[153] About 20 minutes later the Tokyo railroad telegraph center realized that the main line telegraph had stopped working just north of Hiroshima. From some small railway stops within 16 km (9.9 mi) of the city came unofficial and confused reports of a terrible explosion in Hiroshima. All these reports were transmitted to the headquarters of the Imperial Japanese Army General Staff.[154]
Military bases repeatedly tried to call the Army Control Station in Hiroshima. The complete silence from that city puzzled the General Staff; they knew that no large enemy raid had occurred and that no sizable store of explosives was in Hiroshima at that time. A young officer was instructed to fly immediately to Hiroshima, to land, survey the damage, and return to Tokyo with reliable information for the staff. It was felt that nothing serious had taken place and that the explosion was just a rumor.[154]
The staff officer went to the airport and took off for the southwest. After flying for about three hours, while still nearly 160 km (99 mi) from Hiroshima, he and his pilot saw a great cloud of smoke from the bomb. In the bright afternoon, the remains of Hiroshima were burning. Their plane soon reached the city, around which they circled in disbelief. A great scar on the land still burning and covered by a heavy cloud of smoke was all that was left. They landed south of the city, and the staff officer, after reporting to Tokyo, began to organize relief measures.[154]
Events of August 7–9
Brownish leaflet covered in Japanese writing
Leaflet AB11,[155] with information on the Hiroshima bomb and a warning to civilians to petition the Emperor to surrender was dropped over Japan beginning on August 9,[155] by the 509th Composite Group on the bombing mission. Although it is not identified by them, an AB11 is in the possession of the Nagasaki Atomic Bomb Museum.[156]
Truman announcing the bombing of Hiroshima
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President Truman announces the bombing of Hiroshima.
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After the Hiroshima bombing, Truman issued a statement announcing the use of the new weapon. He stated, "We may be grateful to Providence" that the German atomic bomb project had failed, and that the United States and its allies had "spent two billion dollars on the greatest scientific gamble in history—and won." Truman then warned Japan:
If they do not now accept our terms, they may expect a rain of ruin from the air, the like of which has never been seen on this earth. Behind this air attack will follow sea and land forces in such numbers and power as they have not yet seen and with the fighting skill of which they are already well aware.[157]
The Japanese government did not react. Emperor Hirohito, the government, and the war council considered four conditions for surrender: the preservation of the kokutai (Imperial institution and national polity), assumption by the Imperial Headquarters of responsibility for disarmament and demobilization, no occupation of the Japanese Home Islands, Korea, or Formosa, and delegation of the punishment of war criminals to the Japanese government.[158]
The Soviet Foreign Minister Vyacheslav Molotov informed Tokyo of the Soviet Union's unilateral abrogation of the Soviet–Japanese Neutrality Pact on August 5. At two minutes past midnight on August 9, Tokyo time, Soviet infantry, armor, and air forces had launched the Manchurian Strategic Offensive Operation.[159] Four hours later, word reached Tokyo of the Soviet Union's official declaration of war. The senior leadership of the Japanese Army began preparations to impose martial law on the nation, with the support of Minister of War Korechika Anami, in order to stop anyone attempting to make peace.[160]