What was the codename for the proposed second phase of the Allied invasion of Japan?

Operation Coronet was the proposed second phase of the Allied invasion of Japan.

Coronet was intended to follow Operation Olympic, which would have captured southern Kyushu. The second operation was planned for the Kanto Plain on Honshu, the main Japanese island, with Tokyo as the principal strategic objective. Planners expected captured bases in Kyushu to provide air support for the later assault.

Both operations were components of Operation Downfall, the overall invasion plan. Downfall became unnecessary after Japan accepted the Allied surrender terms in August 1945. Coronet was therefore never launched, and its planned landing areas did not become battlefields.

The names can be confusing because Olympic and Coronet were not separate wars or independent surrender plans. They were sequential stages of one proposed campaign. The Japanese counterpart, Operation Ketsugō, was a defensive plan for resisting the invasion, not an Allied operation. The eventual occupation began under very different circumstances after the surrender ceremony.