Nagasaki was hit by the second atomic bomb on August 9, 1945. The bomb, code-named Fat Man, was dropped by the United States three days after Hiroshima was attacked.
The B-29 bomber Bockscar carried the weapon. Its original target was Kokura, but cloud cover and smoke obscured the city, so the crew turned toward the secondary target, Nagasaki. The bomb detonated over the Urakami Valley, an industrial area containing factories and other facilities.
The Nagasaki bombing occurred on the same date that Soviet forces began their invasion of Japanese-held Manchuria. Japan’s government faced pressure from the atomic attacks, Soviet entry into the war, and the continuing military situation. Hirohito announced acceptance of the Potsdam Declaration on August 15, and the formal surrender was signed on September 2.