Hiroshima was the primary target of the first atomic bombing on 6 August 1945.
The United States Army Air Forces used a B-29 bomber named Enola Gay to drop the uranium bomb known as Little Boy. Hiroshima was selected because it was an important military and industrial center and had not previously suffered extensive conventional bombing. Clear weather allowed the crew to identify the city during the mission.
Kokura and Nagasaki were listed as alternative targets for the same mission. Nagasaki was ultimately bombed three days later, on 9 August, after weather conditions prevented the aircraft from attacking Kokura. The bombings occurred alongside the Soviet Union’s declaration of war against Japan and invasion of Japanese-held territory in Manchuria.
The bombings were major factors in the surrender crisis, but historians continue to debate their relative importance alongside the Soviet entry into the war, the naval blockade, conventional bombing, and Japan’s internal political struggle. Hiroshima was the first city attacked with a nuclear weapon in warfare.