What was the planned second stage of Operation Downfall, aimed at the area near Tokyo?

Operation Coronet was the planned second stage of Operation Downfall, aimed at the Kantō Plain near Tokyo. It was intended to follow Operation Olympic, the proposed invasion of southern Kyushu.

Coronet was scheduled for spring 1946, after Allied forces had established bases and airfields during Olympic. The Kantō Plain was strategically important because it included Tokyo and a large concentration of Japan’s population, industry, government, and transportation networks.

The plan was never executed because Japan surrendered in August 1945. Japanese military planners had anticipated that the Allies would eventually attack the home islands and developed Operation Ketsugō to resist the invasion.

Coronet is sometimes mistaken for Olympic because both were parts of Downfall. Olympic referred to the Kyushu landings; Coronet referred to the later Honshu operation. Together, they formed the main invasion concept prepared by Allied planners.