IV.Japan's Claim of Sovereignty over Diaoyu Dao Is Totally Unfounded
On March 8, 1972, Japan's Ministry of Foreign Affairs issued the Basic View on the Sovereignty over the Senkaku Islands in an attempt to explain the Japanese government's claims of sovereignty over Diaoyu Dao. First, Japan claims that Diaoyu Dao was "terra nullius" and not part of Pescadores, Formosa [Taiwan] or their affiliated islands which were ceded to Japan by the Qing government in accordance with the Treaty of Shimonoseki. Second, Japan claims that Diaoyu Dao was not included in the territory which Japan renounced under Article 2 of the Treaty of San Francisco, but was placed under the administration of the United States as part of the Nansei Islands in accordance with Article 3 of the said treaty, and was included in the area for which the administrative rights were reverted to Japan in accordance with the Okinawa Reversion Agreement. Third, Japan claims that China didn't regard Diaoyu Dao as part of Taiwan and had never challenged the inclusion of the islands in the area over which the United States exercised administrative rights in accordance with Article 3 of the Treaty of San Francisco.
Such claims by Japan fly in the face of facts and are totally unfounded.
Diaoyu Dao belongs to China. It is by no means "terra nullius". China is the indisputable owner of Diaoyu Dao as it had exercised valid jurisdiction over the island for several hundred years long before the Japanese people "discovered" it. As stated above, voluminous Japanese official documents prove that Japan was fully aware that according to international law, Diaoyu Dao has long been part of China and was not "terra nullius". Japan's act to include Diaoyu Dao as "terra nullius" into its territory based on the "occupation" principle is in fact an illegal act of occupying Chinese territory and has no legal effect according to international law.
Diaoyu Dao has always been affiliated to China's Taiwan Island both in geographical terms and in accordance with China's historical jurisdiction practice. Through the unequal Treaty of Shimonoseki, Japan forced the Qing court to cede to it "the island of Taiwan, together with all islands appertaining or belonging to it", including Diaoyu Dao. International legal documents such as the Cairo Declaration and the Potsdam Proclamation provide that Japan must unconditionally return the territories it has stolen from China. These documents also clearly define Japan's territory, which by no means includes Diaoyu Dao. Japan's attempted occupation of Diaoyu Dao, in essence, constitutes a challenge to the post-war international order established by such legal documents as the Cairo Declaration and the Potsdam Proclamation and seriously violates the obligations Japan should undertake according to international law.
Diaoyu Dao was not placed under the trusteeship established by the Treaty of San Francisco, which was signed between the United States and other countries with Japan and is partial in nature. The United States arbitrarily expanded the scope of trusteeship to include Diaoyu Dao, which is China's territory, and later "returned" the "power of administration" over Diaoyu Dao to Japan. This has no legal basis and is totally invalid according to international law. The government and people of China have always explicitly opposed such illegal acts of the United States and Japan.