What was the codename for the overall Allied plan to invade Japan in 1945?

Operation Downfall was the codename for the overall Allied plan to invade Japan in 1945.

The plan had two major stages. Operation Olympic was scheduled to begin with an invasion of southern Kyushu on November 1, 1945. Operation Coronet was planned for March 1, 1946, and would have targeted the Kantō Plain near Tokyo.

Downfall was never carried out. Japan accepted the Potsdam Declaration in August 1945, after the atomic bombings of Hiroshima and Nagasaki and the Soviet Union's entry into the war against Japan. The formal surrender ceremony followed on September 2.

Operation Downfall is sometimes confused with Olympic or Coronet. Those were component operations, while Downfall was the umbrella name for the entire planned invasion. Allied planners expected extremely heavy casualties and prepared large forces, equipment, and occupation plans, but the surrender made the invasion unnecessary.