Diaoyu Islands dispute

The Senkaku Islands dispute, or Diaoyu Islands dispute, concerns a territorial dispute over a group of uninhabited islands known as the Senkaku Islands in Japan, the Diaoyu Islands in the People's Republic of China (PRC), and Tiaoyutai Islands in the Republic of China (ROC or Taiwan). Aside from a 1945 to 1972 period of administration by the United States as part of the Ryukyu Islands, the archipelago has been controlled by Japan since 1895. According to Lee Seokwoo, the People's Republic of China (PRC) started taking up the question of sovereignty over the islands in the latter half of 1970 when evidence relating to the existence of oil reserves surfaced.Taiwan (Republic of China) also claims the islands. The territory is close to key shipping lanes and rich fishing grounds, and there may be oil reserves in the area.

Japan argues that it surveyed the islands in the late 19th century and found them to be terra nullius (Latin: land belonging to no one); subsequently, China acquiesced to Japanese sovereignty until the 1970s. The PRC and the ROC argue that documentary evidence prior to the First Sino-Japanese War indicates Chinese possession and that the territory is accordingly a Japanese seizure that should be returned as the rest of Imperial Japan's conquests were returned in 1945.

Although the United States does not have an official position on the merits of the competing sovereignty claims, the islands are included within the Treaty of Mutual Cooperation and Security between the United States and Japan, meaning that a defense of the islands by Japan would require the United States to come to Japan's aid.

In September 2012, the Japanese government purchased three of the disputed islands from their "private owner", prompting large-scale protests in China. As of early February 2013, the situation has been regarded as "the most serious for Sino-Japanese relations in the post-war period in terms of the risk of militarised conflict."

...
Wikipedia