What proposed Allied operation would have invaded Japan's home islands in late 1945?

Operation Downfall was the proposed Allied operation to invade Japan's home islands in late 1945 and 1946. It was canceled after Japan surrendered before the invasion could begin.

Downfall had two planned stages. Operation Olympic was scheduled to land on southern Kyushu in November 1945, while Operation Coronet was planned for the Kanto Plain near Tokyo in spring 1946. The plans called for enormous forces, supported by bases captured in the first phase and by the Allied naval and air power already concentrated in the Pacific.

The operation never took place. Japan's surrender followed the atomic bombings of Hiroshima and Nagasaki, the Soviet declaration of war, and the Soviet invasion of Japanese-held territory. Because Downfall remained a plan rather than an executed campaign, estimates of casualties and the likely course of the invasion vary widely. It is often confused with Olympic or Coronet, which were its component operations.