Nagasaki was hit by the second atomic bomb on 9 August 1945, days before Japan's surrender announcement.
The United States dropped the plutonium implosion bomb known as “Fat Man” over Nagasaki. The intended primary target was Kokura, but cloud cover and smoke led the aircraft to use Nagasaki as the target instead.
The bombing followed the attack on Hiroshima three days earlier. On the same day, Soviet forces began their invasion of Japanese-held Manchuria. These events created an intense crisis for Japan's leadership, which was divided over whether and how to accept the Potsdam Declaration.
Emperor Hirohito's recorded surrender address was broadcast on 15 August. The formal surrender was then signed on 2 September aboard USS Missouri. The bombings were part of a wider set of military, diplomatic, and political pressures that brought the Pacific War to an end.