Japan expands continental shelf in search of rare metals amid China’s opposition

A revised Cabinet order took effect designating a significant portion of the Ogasawara Plateau sea area as part of its continental shelf, an area of around 120,000 square kilometres. Its move to enlarge the shelf has triggered opposition from China.

“The expanded continental shelf represents around half of the area of Japan’s Honshu main island,” said Yoshifumi Matsumura, minister for ocean policy, on June 25 when the Cabinet approved the expansion.

“We will be able to exercise our sovereign rights to explore the continental shelf and develop natural resources,” he said.

The government said it has confirmed the existence of a cobalt-rich crust, including rare metals, in the region. Cobalt is a metal that is used for electric vehicle batteries.

The enlargement of the continental shelf, a part of a continent submerged in a relatively shallow part of the sea, was first proposed in an ocean policy the Japanese government adopted in 2014.

To have its continental shelf recognised beyond its exclusive economic zone, Japan needed the approval of an institution established under the UN Convention on the Law of the Sea on the continuity of the seabed topography and agreement from relevant countries, which in this case was solely the United States.

Following consultations with Washington, Japan set the area for expansion in December 2023.

China has criticised Japan’s move. Foreign Ministry spokeswoman Mao Ning said on June 27 that the expansion “contravenes the stipulations of UN Convention on the Law of the Sea and universal practice”.

Rare earth minerals are crucial for hi-tech products such as batteries and semiconductors. China, a major producer of them, has apparently been seeking to dominate industries where it already holds a large