The atomic bomb was dropped on Nagasaki on August 9, 1945.
The plutonium implosion weapon Fat Man was carried by the B-29 bomber Bockscar and detonated over Nagasaki at about 11:02 a.m. local time. The mission followed the bombing of Hiroshima three days earlier and occurred on the same day that Soviet forces began invading Japanese-held Manchuria.
Nagasaki was not the mission's first-choice target. Kokura had been designated as the primary target, but cloud and smoke prevented the crew from making the required visual identification. The aircraft therefore proceeded to Nagasaki, where a break in the weather allowed the bomb to be released.
The bombing was one of the major events preceding Japan's surrender announcement. The formal surrender ceremony came later, on September 2, aboard USS Missouri.