Article 8 of the Potsdam Declaration (to the terms of which Japan conceded by signing the San Francisco Peace Treaty in 1972) states:
Japanese sovereignty shall be limited to the islands of Honshu, Kyushu, Shikoku, and such minor islands as we determine.
The Allies' list of minor islands pointedly excluded Tokto/ Takeshima, on which the Republic of Korea maintains an outpost but over which Japan asserts territorial claims (as part of Shimane prefecture), as it does the Senkaku Island chain, source of much recent controversy between Japan and neighbors China and Taiwan.
My personal take on the status of the disputed islands is that while the Potsdam Declaration/ San Francisco Treaty does not provide for their ultimate designation, neither does it authorize or encourage Japan to assert its prior claims to these territories. Tokyo's broad interpretation of Allied 'policy' seems disingenuous, given that the Allies aimed to dismember the Japanese Empire, not pave the way for its post-war reconstruction.
The Japanese Ministry of Foreign Affairs explains,
1.The Allies designated the areas where Japan, which was under the Allied occupation, had to cease the exerting political and administrative power and the areas where it was banned from engaging in fishing or whaling, which included Takeshima. These directives, however, stated that they should not be construed as an indication of Allied policy relating to the ultimate determination of the assignment of Japanese sovereign territory.
2.The descriptions in the related Supreme Commander for the Allied Powers Instruction Note (SCAPIN) documents are as follow:
(1) SCAPIN No. 677
(a) In January 1946, the Allies issued SCAPIN No. 677 to instruct Japan to provisionally cease exerting or attempting to exert political or administrative power over some areas.
(b) Article 3 of the note states, "For the purpose of this directive, Japan is defined to include the four main islands of Japan (Hokkaido, Honshu, Kyushu and Shikoku) and the approximately 1,000 smaller adjacent islands, including the Tsushima Islands and the Ryukyu (Nansei) Islands north of 30 degrees North Latitude (excluding Kuchinoshima Island)," and listed Utsuryo Island, Cheju Island, the Izu Islands, the Ogasawara Islands and Takeshima as the areas "not included" with those where Japan was allowed to exert political or administrative power.
(c) Article 6 of the same note, however, states, "Nothing in this directive shall be construed as an indication of Allied policy relating to the ultimate determination of the minor islands referred to in Article 8 of the Potsdam Declaration." (Potsdam Declaration, Article 8: "Japanese sovereignty shall be limited to the islands of Honshu, Hokkaido, Kyushu, Shikoku and such minor islands as we determine.")
(2) SCAPIN No. 1033
(a) In June 1946, the Allies issued SCAPIN No. 1033 to establish the so-called "MacArthur Line" and designate the areas where Japanese people were permitted to engage in fishing and whaling.
(b) Article 3 of the note states "Japanese vessels or personnel thereof will not approach closer than 12 miles from Takeshima nor have any contact with the said island."
(c) Article 5 of the same instruction note, however, states, "The present authorization is not an expression of allied policy relative to ultimate determination of national jurisdiction, international boundaries or fishing rights in the area concerned or in any other area."
3.The abolishment of the "MacArthur Line" was directed in April 25 1952, and three days after, on April 28, the San Francisco Peace Treaty came into effect, which consequently nullified the directive to cease Japan's political and administrative power in the aforementioned areas.
The ROK claims that the Allies did not recognize Takeshima as part of Japan's territory based on the SCAPIN documents mentioned above, and includes them in the evidence for its claim for the sovereignty over Takeshima. However, both of the SCAPIN documents clearly state that they shall not be construed as an indication of Allied policy relating to the ultimate determination of the assignment of Japanese sovereignty, and therefore such claims are obviously not the case.
The territory of Japan was determined by the San Francisco Peace Treaty, which subsequently came into effect. This clearly shows that none of the treatment of Takeshima prior to the effect of that Treaty affects the title to Takeshima.