What region of Japan was the planned target of Operation Coronet?

The Kantō Plain was the planned target of Operation Coronet.

Coronet was the second stage of Operation Downfall, the proposed Allied invasion of Japan. It was intended to land on the Kantō Plain on Honshū, the main Japanese island, and advance toward Tokyo. The tentative start date was March 1, 1946.

The plan envisioned two major U.S. Army thrusts. The First Army would land near Kujūkuri Beach on the Bōsō Peninsula, while the Eighth Army would land near Hiratsuka on Sagami Bay. Together, these forces would attack the area surrounding Japan’s capital.

Coronet was designed to follow Operation Olympic, which would have captured southern Kyūshū in November 1945. Japan surrendered before either operation began. Because the planned invasion was canceled, later claims about its exact casualties remain estimates rather than recorded battlefield totals.