Which proposed operation targeted the Kantō Plain near Tokyo in spring 1946?

Operation Coronet was the proposed Allied invasion of the Kantō Plain near Tokyo in spring 1946.

Coronet was the second stage of Operation Downfall, following Operation Olympic’s planned attack on southern Kyushu. The Kantō Plain was selected because it contained Tokyo and offered the space needed for a major invasion and buildup of forces.

The tentative date for Coronet was March 1, 1946, known as Y-Day. Initial plans assigned large American forces to landing areas around Sagami Bay and the Bōsō Peninsula. Additional formations, including a proposed Commonwealth corps, would have reinforced the beachhead.

Japan’s surrender in August 1945 made Coronet unnecessary. The operation is sometimes confused with Downfall, but Downfall was the overall invasion plan, while Coronet was its planned Honshu phase. Olympic was the separate Kyushu phase.