What was the Allied invasion plan for Japan that was canceled after Japan surrendered in 1945?

Operation Downfall was the Allied invasion plan for Japan that was canceled after Japan surrendered in 1945.

The proposed operation had two major stages. Operation Olympic was planned for November 1945 and would have invaded southern Kyūshū. Operation Coronet was planned for spring 1946 and would have attacked the Kantō Plain near Tokyo on Honshu. Together, these operations were intended to force the defeat of Japan on its home islands.

Downfall was never carried out because Japan surrendered after the atomic bombings of Hiroshima and Nagasaki, the Soviet declaration of war, and the Soviet invasion of Manchuria. If executed, it would have been among the largest amphibious operations in history. Japanese planners had prepared their own defense plan, Operation Ketsugō, which should not be confused with the Allied plan.