Senkaku Islands Dispute

The Senkaku Islands — called Diaoyu in mainland China and Diaoyutai in Taiwan — are a chain of five small islets and three rocks in the East China Sea, roughly between Okinawa, Taiwan, and mainland China. Japan administers the islands and treats sovereignty as settled; the People's Republic of China and the Republic of China (Taiwan) both contest that claim.

Japan incorporated the islands in January 1895, shortly before the Treaty of Shimonoseki ended the First Sino-Japanese War. After World War II the islands fell under U.S. administration along with Okinawa and were returned to Japan under the 1971 Okinawa Reversion Agreement, which took effect in 1972. Beijing and Taipei began publicly asserting claims in the early 1970s, after a 1968 UN ECAFE survey suggested possible hydrocarbon reserves on the surrounding continental shelf.

Key flashpoints include:

• September 2010: A Chinese trawler captain was detained after colliding with Japan Coast Guard vessels near the islands, triggering a diplomatic crisis and a reported Chinese slowdown of rare-earth exports to Japan.
• September 2012: The Japanese government purchased three of the islands from a private owner. Large anti-Japanese protests erupted across Chinese cities, and Beijing began routine patrols inside the contiguous zone and territorial sea.
• November 2013: China declared an East China Sea Air Defense Identification Zone (ADIZ) covering the islands, which Japan, the United States, and South Korea refused to recognize.

The dispute carries weight beyond the rocks themselves. It implicates fisheries, potential seabed energy, and the delimitation of exclusive economic zones under UNCLOS. It is also a test of the U.S.–Japan Security Treaty: successive U.S. administrations, including statements by Presidents Obama (2014) and Biden (2021), have confirmed that Article V applies to territories under Japanese administration, including the Senkakus — without taking a position on underlying sovereignty.