Nagasaki was struck by the atomic bomb called Fat Man on August 9, 1945, shortly before Japan surrendered. The plutonium weapon was dropped by the B-29 bomber Bockscar.
Fat Man exploded at approximately 11:02 a.m. local time. Nagasaki was a major industrial and port city, with factories connected to shipbuilding and military production. The bomb caused enormous destruction and killed tens of thousands of people immediately and during the following months.
Hiroshima had been bombed three days earlier by Little Boy, a uranium weapon. The Soviet Union also declared war on Japan on August 8 and invaded Japanese-held Manchuria on August 9. Japanese leaders faced these rapidly escalating military and political shocks while debating surrender.
Japan communicated its willingness to accept the Potsdam Declaration on August 10, subject to preserving the emperor’s position. Emperor Hirohito later announced the decision publicly, and the formal surrender was signed in Tokyo Bay on September 2.