The atomic bomb named Fat Man was dropped on Nagasaki on 9 August 1945.
Fat Man was a plutonium implosion-type nuclear weapon carried by the B-29 bomber Bockscar. The bomb detonated over Nagasaki at approximately 11:02 a.m. local time. It was the second nuclear weapon used in warfare, following Little Boy's attack on Hiroshima three days earlier.
Nagasaki had been a major industrial and military center, including facilities linked to Mitsubishi. The bomb exploded over the Urakami Valley, where terrain reduced some effects compared with a flatter city, but the destruction and loss of life remained catastrophic. Tens of thousands died in the initial attack and its aftermath.
The Nagasaki bombing occurred on the same day that Soviet forces began invading Japanese-held Manchuria. Japan's leaders faced both developments while debating surrender. Emperor Hirohito announced Japan's decision six days later, and the formal surrender was signed on 2 September.