Facts do not lie:
The Diaoyu islands have been part of China since Ming Dynasty, serving as important fishing grounds administered by the province of Taiwan. This can be fully proven by history and is legally well-founded".
Taiwan was ceded to Japan in the Treaty of Shimonoseki in 1895, after the Sino-Japanese war.
Taiwan was returned to China in 1945 after the surrender of the Empire of Japan on September 2, 1945.
On September 8, 1951, Japan signed the Treaty of Peace with Japan (commonly known as the Treaty of San Francisco or San Francisco Peace Treaty) with 48 nations. Article 3 of the treaty states that Japan will concur in any proposal of the United States to the United Nations to place under its trusteeship system, with the United States as the sole administering authority, Nansei Shoto south of 29deg. north latitude (including the Ryukyu Islands and the Daito Islands), Nanpo Shoto south of Sofu Gan (including the Bonin Islands, Rosario Island and the Volcano Islands) and Parece Vela and Marcus Island. Pending the making of such a proposal and affirmative action thereon, the United States will have the right to exercise all and any powers of administration, legislation and jurisdiction over the territory and inhabitants of these islands, including their territorial waters.
Due to the ongoing Chinese Civil War, neither the Republic of China nor the People's Republic of China were invited to the San Francisco Peace Conference, and neither were parties to the San Francisco Treaty.
On June 17, 1971, a reversion was agreed between Japan and USA concerning the Ryukyu Islands and the Daito Islands. This had created world-wide uproars and protests by Chinese.
china should be part of mongolia if that the case