What was the overall Allied invasion plan for Japan called before its cancellation in 1945?

The overall Allied invasion plan for Japan was called Operation Downfall.

Downfall was the planned invasion of 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 Tokyo Plain on Honshu. The first landings were scheduled for late 1945, with the second stage planned for 1946.

The plans required enormous forces, shipping, aircraft, and supplies. Allied planners also expected severe resistance because Japanese forces were preparing for a homeland defense involving regular troops, militia, and civilian mobilization.

Japan’s acceptance of the Potsdam Declaration in August 1945 made Downfall unnecessary, so neither Olympic nor Coronet was carried out. Operation Downfall is therefore a planned operation, unlike the actual occupation that followed Japan’s surrender.