Japan formally protested to Beijing on Tuesday after a Chinese guided-missile destroyer conducted a live-fire exercise within what Tokyo considers its exclusive economic zone around the remote Okinotori atoll, the first time the Japanese defence ministry has publicly acknowledged such a drill. The Luyang III-class vessel fired machine guns roughly 180 kilometres southwest of the feature on Sunday morning, while a Russian Steregushchiy-class frigate remained in the vicinity, according to the Japanese Joint Staff. Tokyo said the Chinese warship issued a radio warning to nearby ships immediately before the exercise, but the government told Beijing through diplomatic channels that the activity “could pose a danger to the navigation of vessels in the area.”

The incident highlights a sharp divergence in legal and territorial interpretations. Japan claims Okinotori as its southernmost island, generating a 200-nautical-mile exclusive economic zone; China argues the feature is a rock that cannot sustain human habitation or economic life of its own, and therefore no such zone exists. Beijing has not commented publicly on the protest, but its foreign ministry has previously stated that joint Sino-Russian naval patrols in the Pacific are routine and lawful. Moscow, which has deepened military coordination with China, did not issue a separate statement, though the Russian frigate’s presence was confirmed by Japanese surveillance. Separately, a Russian frigate, the Neustrashimy, carried out a live-fire artillery exercise in international waters 40 nautical miles south of Plymouth on Monday, after informing the Royal Navy in advance. The UK Ministry of Defence said the operation was monitored throughout and posed no threat to national security, a contrast to the Japanese protest.

Viewed from Tokyo, the drill is part of a pattern of intensified Sino-Russian military activity around the Japanese archipelago. Defence Minister Shinjiro Koizumi, speaking in Britain, linked the live-fire exercise to a recent string of joint bomber flights and a Chinese submarine-launched ballistic missile test, describing “deepening military cooperation between China and Russia.” Japan’s defence white paper has consistently labelled this coordination as the most serious strategic challenge facing the country. In response, Tokyo is accelerating plans to raise defence spending to 2 per cent of GDP by 2027 and is strengthening surveillance capabilities along its southwestern island chain. The episode also adds friction to already strained Sino-Japanese relations, which deteriorated after Prime Minister Sanae Takaichi suggested in November that Japan could intervene militarily if China attacked Taiwan.

Western naval analysts note that live-fire drills in international waters are not prohibited under the law of the sea, and the Japanese defence ministry acknowledged that the Chinese exercise did not violate international rules. The UK case, where a Russian warship fired in the Channel with prior notification and without triggering a diplomatic protest, illustrates how such events are often managed when territorial claims are not in dispute. In the Pacific, however, the overlapping sovereignty claims and the broader strategic rivalry between China and the US-Japan alliance raise the stakes. Tokyo has not announced any further diplomatic or military measures beyond the protest, but the Japanese Maritime Self-Defence Force continues to monitor Chinese and Russian naval movements in the region.