Operation Olympic was the planned Allied invasion of Kyushu, scheduled for November 1945 if Japan did not surrender.
Olympic formed the first stage of Operation Downfall, the larger proposed invasion of the Japanese home islands. Its objective was to capture the southern part of Kyushu and establish airfields and positions for a later assault on the Tokyo region.
The second stage, Operation Coronet, was planned for the Kantō Plain near Tokyo in spring 1946. Operation Downfall was canceled after Japan surrendered following the atomic bombings of Hiroshima and Nagasaki and the Soviet declaration of war.
These plans were not carried out, so casualty estimates varied widely and remained predictions rather than battlefield totals. Operation Olympic is often confused with Downfall: Olympic was the Kyushu operation, while Downfall was the overall invasion plan that included Olympic and Coronet.