The following is a synopsis of the impact of international agreements on the legal status of Taiwan:
1. Article 2 of the Treaty of Shimonoseki (1895) ceded Formosa, her dependencies, and the Pescadores from China to Japan in "perpetuity and full sovereignty." Japan's sovereignty over the islands would not be disputed by China or any other state for the next 50 years.
2. In paragraph 3 of the Cairo Declaration (1943), the United States, Great Britain, and China declared that "it is their purpose that Japan shall be stripped of all the islands in the Pacific which she has seized or occupied since the beginning of the First World War in 1914, and that all the territories Japan has stolen from the Chinese, such as Manchuria, Formosa, and the Pescadores, shall be restored to the Republic of China." This and the following two declarations were unilateral statements of intent, not legally binding on the declarants, much less so Japan, the title-holder to Formosa. The Cairo Declaration, intended only as a press release, was issued without signatures. From their language, it is clear that the conference statements are not of the variety of declarations that possess legal force. Indeed, some of the provisions of at least one of the declarations were repudiated by one of the declarants, the United States of America, in her ratification of the Treaty of Peace with Japan. Moreover, the term "restored" was used in reference to the Republic of China without specifying, though assuming, the Republic of China as the successor to the "Ta Ching Empire," the legal person that had ceded Formosa to Japan. The Republic of China never held possession of Formosa, nor did she claim rights to her until the onset of war with Japan.
4. Section 3-b(8) of Annex II of the Potsdam Declaration (1945) makes reference to the Cairo Declaration stating "The terms of the Cairo Declaration shall be carried out and Japanese sovereignty shall be limited to the islands of Honshu, Hokkaido, Kyushu, Shikoku and such minor islands as we determine."
5. Under the Instrument of Surrender signed in September 1945 by Japan and the Allies, Japan explicitly accepted the provisions of the Potsdam Declaration, and thus implicitly accepted the provision of the Cairo Declaration "that all the territories Japan has stolen from the Chinese, such as Manchuria, Formosa, and the Pescadores, shall be restored to the Republic of China." The Instrument of Surrender gave legal effect to the Allied Conference Declarations hitherto absent. However, the Instrument was a record only of provisional arrangements, a modus vivendi, that anticipated replacement by a more permanent and detailed settlement. The Instrument required no ratification and does not have the legal force of a treaty.
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