Nagasaki was hit by the second atomic bomb on 9 August 1945, three weeks before Japan’s formal surrender.
The United States dropped the plutonium implosion bomb known as Fat Man over Nagasaki on 9 August. The bomb was originally aimed at Kokura, but clouds and smoke obscured the target. The B-29 bomber Bockscar diverted to its secondary target, Nagasaki, where the weapon detonated at about 11:02 a.m. local time.
The bombing followed the destruction of Hiroshima by the uranium bomb Little Boy on 6 August. On the same day as the Nagasaki attack, the Soviet Union began its invasion of Japanese-held Manchuria. These simultaneous developments placed intense pressure on Japan’s leadership.
The precise role of the bombings and the Soviet entry in Japan’s decision remains an important subject of historical debate. Japan announced its surrender on 15 August, and representatives formally signed the surrender instrument aboard USS Missouri on 2 September. Nagasaki’s name is sometimes confused with Kokura because Kokura was the original primary target.