What was the planned Allied invasion of Japan in 1945–46 called?

The planned Allied invasion of Japan in 1945–46 was called Operation Downfall.

Downfall was the overall plan for invading the Japanese home islands if Japan did not surrender. It had two major stages: Operation Olympic, aimed at southern Kyushu, and Operation Coronet, aimed at the Kantō Plain near Tokyo on Honshu.

Olympic was scheduled to begin in November 1945, while Coronet was planned for March 1946. The projected invasion involved enormous Allied forces and was expected to produce severe casualties on both sides, although estimates varied considerably.

Japan's surrender in August 1945 meant that Downfall was never carried out. The atomic bombings of Hiroshima and Nagasaki, the Soviet declaration of war against Japan, and Japan's internal political crisis all formed part of the final chain of events leading to surrender.