What was the name of the planned first phase of Operation Downfall, aimed at southern Kyūshū?

Operation Olympic was the planned first phase of Operation Downfall, aimed at southern Kyūshū.

The invasion was scheduled to begin on 1 November 1945. Allied forces intended to seize the southern third of Kyūshū, Japan’s southernmost main island, and build air bases there. Those bases would have supported the later invasion of the Kantō Plain near Tokyo, designated Operation Coronet.

Olympic was expected to involve a very large naval armada, including hundreds of warships and dozens of aircraft carriers. The landing plan identified beaches and approach areas around Miyazaki, Ariake and Kushikino. Okinawa, captured by the Allies in June 1945, would have served as a major staging base.

The plan was never carried out because Japan surrendered in August. Operation Olympic is sometimes mistakenly used as a name for the entire planned invasion, but Downfall was the overall operation. Olympic referred specifically to the Kyūshū phase, while Coronet referred to the later Honshū phase.