On September 8, 1951, the Treaty of Peace with Japan was signed in San Francisco in the United States, and the treaty entered into effect on April 28, 1952. Under this treaty, all of the Nanpo Islands south of Sofu Gan (including the Ogasawara Islands, Nishinoshima and the Kazan Islands) as well as Okinotorishima and Minamitorishima, were placed under the administration of the United States. (Ref. 1)

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