What was the planned Allied operation to invade southern Kyushu after Japan refused to surrender?

Operation Olympic was the planned Allied invasion of southern Kyushu.

It was the first stage of Operation Downfall, the proposed invasion of Japan’s home islands. Olympic was scheduled to begin on 1 November 1945 and aimed to capture the southern portion of Kyushu, Japan’s southernmost main island. The area would have supplied airfields and staging bases for the next phase.

The second stage, Operation Coronet, was planned for the Kanto Plain near Tokyo on Honshu. Together, Olympic and Coronet would have formed a huge amphibious campaign involving hundreds of thousands of personnel and extensive naval and air support.

Operation Olympic was never carried out. Japan accepted the Allied terms in August 1945 after the atomic bombings, the Soviet declaration of war, and the Soviet invasion of Manchuria. The planned invasion was therefore canceled. Olympic is sometimes mistakenly treated as the whole invasion plan; the complete operation was Downfall.