What was the code name for the planned Allied invasion of Japan’s home islands in 1945–1946?

Operation Downfall was the code name for the planned Allied invasion of Japan’s home islands. It was canceled after Japan surrendered in August 1945, before the invasion could begin.

Downfall had two major stages. Operation Olympic was scheduled for November 1, 1945, and would have attacked southern Kyushu. Operation Coronet was planned for spring 1946 and would have targeted the Kanto Plain near Tokyo on Honshu.

The projected operation would have required a huge naval and military force and was expected to produce severe casualties. Japanese forces were preparing their own defense plan, Operation Ketsugo, while Allied planners developed landing and air-support arrangements.

Operation Downfall is often confused with Operation Overlord, the Allied invasion of Normandy in June 1944. Overlord liberated Western Europe; Downfall was a proposed operation that never took place.