6 August 1945
Atomic Bombing of Hiroshima
By the summer of 1945 Germany had surrendered and nearly all of the territory that the Japanese had conquered through 1942 was under Allied control. Nevertheless the Japanese government claimed that the country would fight to the very end, vowing to raise a national civilian militia of some 28 million people to resist any attempted invasion of the home islands. Given the casualties suffered in the battles for Iwo Jima and Okinawa, Allied military planners estimated that as many as a million U.S. servicemen might be lost in an invasion of Japan.

But what no one in Japan—and very few even on the Allied side—realized was that the United States was close to developing a devastating new weapon. The atomic bomb was believed to be so powerful that, if dropped on Japanese cities, the government in Tokyo could be forced to surrender without the need for an invasion. When President Harry S. Truman learned in late July that an atomic bomb had been successfully tested in New Mexico, he was quick to authorize its use against the Japanese.

On July 26 the Allies gave a final warning to Japan—surrender or face the consequences. Then Tokyo ignored the ultimatum, a B-29 bomber called the “Enola Gay” dropped an atomic bomb on the city of Hiroshima. The bomb, nicknamed “Little Boy,” exploded 2,000 feet above the city, and its impact was even more dramatic than expected. An area of 42 square miles was simply devastated, and more than 130,000 people killed or seriously injured. The world had never before experienced an instrument of such destruction.

Histories:
The Atomic Bombings of Hiroshima and Nagasaki
The Effects of Atomic Bombs on Hiroshima and Nagasaki

Campaign Map:
Allied Plans for the Invasion of Japan

Documents:
“The World Will Note”: President Truman Announces the Atomic Bomb
The Decision to Drop the Atomic Bomb

Personal Accounts:
Eyewitness Account by Father John A. Siemes

Photographs:
Col. Paul W. Tibbets, Jr., pilot of the ENOLA GAY, the plane that dropped the atomic bomb on Hiroshima, waves from his cockpit before the takeoff, 6 August 1945
The patient's skin is burned in a pattern corresponding to the dark portions of a kimono worn at the time of the explosion