Which planned 1946 invasion operation targeted Japan’s Kantō Plain near Tokyo?

Operation Coronet was the planned 1946 invasion of Japan’s Kantō Plain near Tokyo.

Coronet was the second phase of Operation Downfall, the proposed Allied invasion of the Japanese home islands. It was tentatively scheduled to begin on March 1, 1946, after Operation Olympic had captured southern Kyūshū and provided bases for continued operations. The target area included the Kantō Plain around Tokyo.

The operation was expected to be larger than Olympic. Planning documents envisaged major landings at Sagami Bay and Kujūkuri Beach, followed by an advance toward Tokyo. Up to 45 U.S. divisions were assigned to the initial and follow-up forces in some plans, compared with 12 divisions in the initial Normandy landings.

Coronet was canceled because Japan surrendered in August 1945. It is often confused with Operation Olympic, the planned Kyūshū landing, or with Downfall, the overall invasion plan. Unlike both of those names, Coronet referred specifically to the planned assault on the Tokyo region.