What was the Allied invasion plan for Japan's home islands called when Japan surrendered?

The planned Allied invasion of Japan's home islands was called Operation Downfall.

Downfall was a proposed two-stage invasion intended for late 1945 and 1946. It was designed to force Japan's defeat if blockade, bombing, and other measures did not produce surrender. The plan was canceled after Japan accepted the Allied terms in August 1945.

Its first stage, Operation Olympic, was scheduled to land on southern Kyūshū in November 1945. Its second stage, Operation Coronet, was intended to attack the Kantō Plain near Tokyo in spring 1946.

Because the invasion never occurred, casualty estimates for Downfall are projections rather than battlefield totals. The scale of the proposed operation was enormous, and planners expected fierce resistance. The cancellation means that Operation Downfall should not be described as an executed campaign.