On 14 August 1945, Japan unconditionally surrendered ending WWII in the Pacific.
This followed the dropping of atomic weapons by the United States.
“Little Boy”, a 15 kiloton of TNT, uranium based bomb destroyed Hiroshima on 6 August 1945 and was deployed by the B29 Superfortress “Enola Gay”.
“Fat Man”, a 21 kiloton of TNT plutonium based atomic weapon, was dropped by the B29 Superfortess “Bockscar” on 9 August 1945 on Nagasaki. The primary target for “Fat Man” was the city of Kokura but that city was obscured by clouds and smoke following the firebombing of the nearby city of Yawata the day before, and so the weapon was deployed at the secondary target of Nagasaki.