HOME
        TheInfoList






Ground units:

US Army Forces, Pacific

(52–54 divisions in total)[7]

Naval units:

United States Pacific Fleet

Air units:
USASTAF Pacific

United States Fifth Air Force
United States Seventh Air Force
United States Thirteenth Air Force

United Kingdom Tiger Force

Ground units:

First General Army

Second General Army

Patriotic Citizens' Fighting Corps[6]

(66 divisions, 36 brigades, and 45 regiments, not counting PCFC units.)[9]

Navy units:
Navy General Command

Air units:
Air General Army

  • Empire of Japan First Air Army
  • Empire of Japan Sixth Air Army

Empire of Japan Third Air Fleet
Empire of Japan Fifth Air Fleet
Empire of Japan Tenth Air Fleet
Empire of Japan Sixth Air Fleet

Empire of Japan Twelfth Air Fleet[6]Strength

United States More than 5,000,000 (projected)[10]
United Kingdom 1,000,000 (projected)[11]

More than 6,000,000 total (projected)

4,335,500 military,[12]
31,550,000 civilian conscripts[13]

35,885,500 total

Operation Downfall was the proposed Allied plan for the invasion of the Japanese Home Islands near the end of World War II. The planned operation was cancelled when Japan surrendered following the atomic bombings of Hiroshima and Nagasaki, the Soviet declaration of war and the invasion of Manchuria.[14] The operation had two parts: Operation Olympic and Operation Coronet. Set to begin in November 1945, Operation Olympic was intended to capture the southern third of the southernmost main Japanese island, Kyūshū, with the recently captured island of Okinawa to be used as a staging area. In early 1946 would come Operation Coronet, the planned invasion of the Kantō Plain, near Tokyo, on the main Japanese island of Honshu. Airbases on Kyūshū captured in Operation Olympic would allow land-based air support for Operation Coronet. If Downfall had taken place, it would have been the largest amphibious operation in history.[15]

Japan's geography made this invasion plan quite obvious to the Japanese as well; they were able to accurately predict the Allied invasion plans and thus adjust their defensive plan, Operation Ketsugō, accordingly. The Japanese planned an all-out defense of Kyūshū, with little left in reserve for any subsequent defense operations. Casualty predictions varied widely, but were extremely high. Depending on the degree to which Japanese civilians would have resisted the invasion, estimates ran up into the millions for Allied casualties.[16]

Planning

Responsibility for the planning of Operation Downfall fell to American commanders Fleet Admiral Chester Nimitz, General of the Army Douglas MacArthur and the Joint Chiefs of Staff—Fleet Admirals Ernest King and William D. Leahy, and Generals of the Army George Marshall and Hap Arnold (the latter being the commander of the U.S. Army Air Forces).[17] At the time, MacArthur was also being considered for promotion to the special "super rank" of six-star General of the Armies, so as to be granted operational authority over other five-star officers. However, the proposal to promote MacArthur was only at the level of informal discussion by the time World War II ended.[18]

At the tim

US Army Forces, Pacific

(52–54 divisions in total)[7]

Naval units:

United States Pacific Fleet

  • United States Third Fleet
  • United States Fifth Fleet
  • United States Seventh Fleet
  • United States United States Pacific Fleet

    Air units:
    USASTAF Pacific

    United States Fifth Air Force
    United States Seventh Air Force
    United States United States Fifth Air Force
    United States Seventh Air Force
    United States Thirteenth Air Force

    United Kingdom Tiger Force

    Ground units:

    First General Army

    • Empire of JapanGround units:

      First General Army

      • Empire of JapanFirst General Army

        Second General Army

        Patriotic Citizens' Fighting Corps[6]

        (66 divisions, 36 brigades, and 45 regiments, not counting PCFC units.)[9]

        Navy units:
        Navy General Command

        • Empire of JapanPatriotic Citizens' Fighting Corps[6]

          (66 divisions, 36 brigades, and 45 regiments, not counting PCFC units.)[9]

          Navy units:
          Navy General Command

          Air units:

          (66 divisions, 36 brigades, and 45 regiments, not counting PCFC units.)[9]

          Navy units:
          Navy General Command

          Air units:
          Air General Army

          • Empire of Japan First Air Army
          • Empire of JapanEmpire of Japan Third Air Fleet
            Empire of Japan Fifth Air Fleet
            Empire of Japan Tenth Air Fleet
            Empire of Japan Sixth Air Fleet

            Empire of Japan Twelfth Air Fleet[6]Strength

            United States

            United States More than 5,000,000 (projected)[10]
            United Kingdom 1,000,000 (projected)[11]

            More than 6,000,000 total (projected)

            4,335,500 military,[12]
            31,550,000 civilian conscripts[13]

            35,885,500 total