OPERATION DOWNFALL

This site is dedicated to gathering information pertinent to Operation DOWNFALL, the allied amphibious assaults on Japan (Operations OLYMPIC and CORONET) planned for 1945 and 1946 and presenting that information in one place. The site focuses on this in two ways: (1) describing the state of Allied and Japanese land, naval, and air forces on/about 1 August 1945—before the impeding surrender began to influence operations and (2) excerpting relevant sections of plans associated with the execution of Operation DOWNFALL—with emphasis on the later versions of those plans.

It should be noted that in August 1945, plans prepared by the Army, Navy, Army Air Forces, and Navy Amphibious Forces their still remained numerous details to be reconciled.

The graphic on the right was included in JCS 1388-4. JCS 1388, titled DETAILS OF THE CAMPAIGN AGAINST JAPAN, was prepared for a meeting with President Truman, June 18, 1945. A summary of the document was read by General of the Army Marshall, as an expression of his views. JCS 1388-4, dated July 11, 1945 was a revised and updated version of that document.