Hiro Shima Naga Saki

                      Hiro Shima, Naga Saki.

In August 1945, during the final stage of the Second World War, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki. The two bombings, which killed at least 129,000 people, remain the only use of nuclear weapons for warfare in human history.





As the Second World War entered its sixth and final year, the Allies had begun to prepare for, what was anticipated to be, a very costly invasion of the Japanese mainland. This was preceded by an immensely destructive firebombing campaign that obliterated many Japanese cities. The war in Europe had concluded when Nazi Germany signed its instrument of surrender on May 8, 1945, but with the Japanese refusal to accept the Allies' demands for unconditional surrender, the Pacific War dragged on. Together with the United Kingdom and China, the United States' calls for the unconditional surrender of the Japanese armed forces in the Potsdam Declaration on July 26, 1945 was buttressed with the threat of "prompt and utter destruction".   


By August 1945, the Allied Manhattan Project had successfully detonated an atomic device and subsequently produced atomic 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 was dropped on Hiroshima on August 6, 1945, followed by a plutonium implosion-type bomb on the city of Nagasaki on August 9.

Background:

Pacific War,

 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. In the Pacific the Allies returned to the Philippines, recaptured Burma, and invaded Borneo. Offensives were undertaken to reduce the Japanese forces remaining in Bougainville, New Guinea and the Philippines. 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.

 

Preparations to invade Japan

 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^. 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. 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.