Why have offshore oil and natural gas deposits caused disputes in the East China Sea?

Disputes over offshore oil and natural gas deposits in the East China Sea arise primarily from overlapping territorial and maritime claims between bordering nations, particularly China and Japan.12

These conflicts are driven by several key factors:

• Overlapping EEZ Claims: Under the United Nations Convention on the Law of the Sea (UNCLOS), coastal states are entitled to an exclusive economic zone (EEZ) extending up to 200 nautical miles from their coasts. Because the sea separating China and Japan is only about 360 nautical miles wide, their claims to these zones overlap significantly.2
• Resource Potential: The discovery of potentially exploitable hydrocarbon reserves—including petroleum and natural gas—beneath the continental shelf has intensified the desire for sovereign control over these waters.12
• Sovereignty over Islands: Disputes are further complicated by conflicting claims over uninhabited islands and rocks, such as the Senkaku Islands (known as the Diaoyu Islands in China). Sovereignty over these features is often linked to the rights to explore and exploit the surrounding seabed resources.13

These tensions highlight the importance of international law in managing resource competition, as nations seek to secure energy supplies while navigating complex maritime boundaries.2