Operation Coronet was planned to invade Honshu, Japan’s largest home island, in 1946.
Coronet formed the second stage of Operation Downfall, the proposed Allied invasion of Japan. Its objective was the Kanto Plain near Tokyo, an area with major political, industrial, and transportation importance. The tentative landing date was March 1, 1946.
The first stage, Operation Olympic, was aimed at southern Kyushu and was scheduled for November 1945. Planners expected captured airfields on Kyushu to support the later assault on Honshu. Japan’s surrender in August 1945 canceled both operations before either began. Honshu is sometimes confused with Kyushu in discussions of Downfall because both islands were invasion targets, but Coronet specifically concerned the Tokyo region on Honshu.