Japan's continental shelf expanded in July by 120,000 square kilometers, equivalent to about 30% of its total national land area, with the addition of an area in Pacific waters east of Chichijima, part of the Ogasawara island chain.

The expansion, achieved through continuous maritime surveys conducted by the Japan Coast Guard, has sparked optimism for potential resource development. The new region is believed to contain valuable deposits of rare metals, including cobalt.

The continental shelf forms part of a country's exclusive economic zone, where the country holds priority rights to resource development. Under the 1982 U.N. Convention on the Law of the Sea, a continental shelf can be extended if continuity is demonstrated on the basis of topographical and geological characteristics.