What was the planned U.S. landing operation in southern Kyūshū under Operation Downfall called?

Operation Olympic was the planned U.S. landing operation in southern Kyūshū under Operation Downfall.

Olympic was designed as the first stage of the proposed invasion of Japan. American forces planned to land on southern Kyūshū on November 1, 1945, seize airfields and ports, and establish a base for later operations. The operation was never launched because Japan surrendered in August and signed the surrender instrument in September.

The second stage of Downfall was Operation Coronet, which would have attacked the Kantō Plain near Tokyo in March 1946. Olympic and Coronet were therefore related but separate plans. Olympic did not refer to the entire invasion of Japan.

Planning for Olympic reflected Allied concerns about Japan’s geography, military preparations, and expected resistance. The United States assembled forces and considered enormous casualty estimates, although historians continue to debate how likely the worst projected losses were. Japan’s surrender made the invasion unnecessary.