Why did a 1970s oil discovery ignite a decades-long island dispute?

Health · Published 7 October 2026 Swipe more like this →

In short: The Senkaku Islands are uninhabited rocks in the East China Sea, yet they sit at the center of a fierce sovereignty battle. While Japan claims they were discovered as terra nullius in the late 19th century, China's interest surged only after evidence of potential oil reserves surfaced in 1970.

The dispute involves a group of five uninhabited islands and three barren rocks, ranging from 0.002km2 to 3.81km2. Japan incorporated the islands in 1895, arguing they were terra nullius—land belonging to no one—following surveys conducted since 1884. However, the People's Republic of China and Taiwan argue that historical evidence prior to the First Sino-Japanese War proves Chinese possession, making the islands a Japanese seizure that should have been returned in 1945.

The tension escalated significantly in the 1970s. According to scholar Lee Seokwoo, the dispute crystallized around 1971 following the Okinawa Reversion Treaty. This coincided with the emergence of evidence regarding oil reserves in the area. Interestingly, prior to the 1970s, neither the PRC nor the ROC made official claims to the islands; many Chinese maps and documents from 1945 through the 1960s actually referred to them by their Japanese names.

The stakes are high: the islands are located near vital shipping lanes and rich fishing grounds. Furthermore, the United States is bound by the 1960 Treaty of Mutual Cooperation and Security to defend Japan, meaning a conflict over these islands could trigger US intervention. In September 2012, Japan's purchase of three islands from a private owner further inflamed tensions, leading China to establish an Air Defense Identification Zone in the East China Sea in November 2013.

The legal debate often hinges on the 'critical date'—the moment the dispute became official. If that date is 1895, the claims shift significantly; if it is 1971, legal scholars like Lee suggest Japan may have a stronger claim due to the lack of Chinese or Taiwanese objection during the preceding 76 years.

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