What was the overall Allied invasion plan for Japan that was canceled after its surrender?

Operation Downfall was the overall Allied plan for invading Japan, and it was canceled after Japan surrendered.

The plan had two major stages. Operation Olympic was scheduled for November 1945 and would have attacked southern Kyushu. Operation Coronet was planned for spring 1946 and would have invaded the Kanto Plain near Tokyo on Honshu. Together, these operations were intended to force the Japanese government to capitulate through the occupation of the home islands.

Downfall was never carried out. Japan’s surrender followed the atomic bombings of Hiroshima and Nagasaki, the Soviet declaration of war, and the Soviet invasion of Manchuria. Because the plan remained unexecuted, its projected casualties were estimates rather than battlefield totals, and historians debate how severe the losses would have been.

Operation Downfall should not be confused with Olympic or Coronet. Downfall was the umbrella plan; Olympic and Coronet were its two planned invasion phases. Japan’s surrender removed the need to launch either phase.