国務省対外政策諮問委員会極東班のジョージ・H・ブレイクスリーが領土小委員会(PWC territorial group)に提出した1943年7月28日の「日本の戦後処理に適用すべき一般原則」(General Principles Applicable to the Post-War Settlement with Japan:T-357)では、日本の領土については、満州を含む全軍事占領地、および民族自決の原則から朝鮮と台湾からの撤退が主張された[3][4][5]。
1944年3月14日には、ブレイクスリー議長が起草した「戦後日本に関する米政府の目標」(The Postwar Objectives of the United States in regard to Japan(PWC108, CAC116))にはこうある[6][4]。
1945年8月11日にアメリカ国務・陸・海軍三省調整委員会(SWNCC)が承認し、8月18日にトルーマン大統領が承認した大統領宛覚書「日本の敗北後における本土占領軍の国家的構成(NationalComposition of Forces to Occupy Japan Proper to the Post-Defeat Period)(SWNCC 70/5)で連合国による分割占領案が記載されている[2]。覚書SWNCC 70/5では、
C.. The United Kingdom, China and the Soviet Union have a responsibility to participate with the United States in the occupation and military control of Japan and the obligation to assume a share in the burden thereof.
7月6日付の合衆国陸海軍最高司令官(大統領)付参謀長ウィリアム・リーヒによる短いメモ(JCS1398/2)には「日本を占領統治するなら、コストを節減し米軍は最小限にとどめるべきだ。米国が日本軍政に主な責任を負うべき理由はない」とあり、その影響でポツダム会談へ向かう代表団は、米軍負担の軽減化のため、連合国による日本共同占領案が高まり、日本降伏の翌8月16日に、ペンタゴンの統合戦争計画委員会(Joint War Plans Committee,JWPC)が起案した日本占領案「日本とその領土の最終占領(Ultimate Occupation of Japan and Japanese Territory)」(JWPC385/1)が成立した[8]。それによれば、
Post World War II Foreign Policy Planning, State Department Records of Harley A. Notter, 1939-1945 "600-T-357 Japan: General Principles Applicable to the Post-War Settlement with Japan" <Sheet No. YE5-21 600-T-357>,U.S. National Archives & Records Administration (RG59),“General Principles Applicable to the Post-War Settlement with Japan” T 357, 28 July 1943.National Diet Library.
Japan: The Postwar Objectives of the United States in regard to Japan (PWC108, CAC116),March 14, 1944,State Department Documents of the Post-War Programs Committee, 1944 "PWC108 Japan: The Postwar Objectives of the United States in regard to Japan"<PWC-1, Roll No.2>,U.S. National Archives & Records Administration (RG59).
MEMORANDUM FOR THE PRESIDENT:NationalComposition of Forces to Occupy Japan Proper to the Post-Defeat Period,August 13, 1945.State Department Records Decimal File, 1945-1949 "740.00119 CONTROL (JAPAN)/18-1845" <Sheet No. SDDF(A)00444>アメリカ国立公文書記録管理局(RG59)。
Dayna Leigh Barnes,Armchair Occupation: American Wartime Planning for Postwar Japan, 1937-1945,2013,The London School of Economics and Political Science
Eiji Takemae,Allied Occupation of Japan,Continuum Intl Pub Group (Sd); Reprint版 (2003)
^ abc MEMORANDUM FOR THE PRESIDENT:NationalComposition of Forces to Occupy Japan Proper to the Post-Defeat Period,August 13, 1945.State Department Records Decimal File, 1945-1949 "740.00119 CONTROL (JAPAN)/18-1845" <Sheet No. SDDF(A)00444>アメリカ国立公文書記録管理局(RG59)。トルーマン「日本の敗北後における本土占領軍の国家的構成」(SWNCC決定)を承認 1945年8月18日 - 国立国会図書館「日本国憲法 資料と解説・第1」。
^Post World War II Foreign Policy Planning, State Department Records of Harley A. Notter, 1939-1945 "600-T-357 Japan: General Principles Applicable to the Post-War Settlement with Japan" <Sheet No. YE5-21 600-T-357>,U.S. National Archives & Records Administration (RG59),“General Principles Applicable to the Post-War Settlement with Japan” T 357, 28 July 1943.National Diet Library.
^Dayna Leigh Barnes,Armchair Occupation: American Wartime Planning for Postwar Japan, 1937-1945,2013,The London School of Economics and Political Science.p55.
^Japan: The Postwar Objectives of the United States in regard to Japan (PWC108, CAC116),March 14, 1944,State Department Documents of the Post-War Programs Committee, 1944 "PWC108 Japan: The Postwar Objectives of the United States in regard to Japan"<PWC-1, Roll No.2>,U.S. National Archives & Records Administration (RG59).
^British Commonwealth Occupation Force 1945–52,James Wood,THE AUSTRALIAN MILITARY CONTRIBUTION TO THE OCCUPATION OF JAPAN, 1945–1952,Australian War Memorial.2016年10月22日閲覧。(James Wood, The forgotten force: the Australian military contribution to the occupation of Japan 1945– 1952, Allen and Unwin, 1998.の抜粋)
^Thomas T.Handy, General, G.S.C.,Acting Chief of Staff to General Carl Spaatz, Commanding General United States Army Strategic Air Forces: Memorandum on Japanese bombing ,WAR DEPARTMENT OFFICE OF THE CHIEF OF STAFF Washington 25, D. C.,July 25, 1945.「The 509 Composite Group, 20th Air Force will deliver its first special bomb as soon as weather will permit visual bombing after about 3 August 1945 on one of the targets: Hiroshima, Kokura, Niigata and Nagasaki. 」