A Chinese official document written in 1950 states that Japan owns the Senkaku group of islands in the East China Sea, which are today claimed by China.
A copy of the document which describes the disputed islands as part of the Ryukyu Islands, today known as Okinawa, was published by the Japanese press.
The document was written in May 1950 by the Chinese Foreign Ministry and refers to the islands by their Japanese name of Senkaku, part of the Ryukyu chain.
The document proves that China regarded the Senkaku Islands as part of the Ryukyus and not of Taiwan, which has been a long held Chinese claim, according to the international press.
Japan and China have tensioned relationships due to the territorial conflict. The conflict is about which of the two countries should hold the ownership of the islands, which are rich in oil, minerals and fish.
Japan announced in September that it bought the islands from its Japanese private owners.
Chinese people held anti-Japan demonstrations following the announcement.