After Japan's foreign minister urged compliance with the award, China's foreign ministry pushed back through statements and briefings, accusing Tokyo of 'hyping' the ruling and lodging representations, Huanqiu reported.

In the exchange, Beijing raised Okinotori head-on: by the award's logic that Itu Aba is a rock rather than an island, Japan would likewise lack grounds to claim a vast exclusive economic zone from the Okinotori reef in the Pacific, the United Daily News reported.

Japan maintains Okinotori qualifies as an island under UNCLOS, while China, Korea and others contend it is a rock and dispute the EEZ.

Positions on the arbitration itself remain split: the Philippines and others demand implementation, while China maintains it does not recognize the ruling.

With maritime legal sparring spreading to the East China Sea and the Pacific, disputes over navigation and resource jurisdiction look set to continue.