On Saturday, China’s coast guard announced that the Xiushan ship formation had replaced the Daishan group to continue what it called “routine law enforcement patrols” in waters east of Taiwan. The rotation, the second in roughly a month, follows a June deployment that Beijing explicitly linked to Japan-Philippines maritime boundary negotiations. The Chinese vessels were tracked by Taiwan’s coast guard approximately 54 nautical miles east of Hualien, a city hosting a major air base, but remained outside Taiwan’s declared restricted waters.

Viewed from Beijing, the patrols are an assertion of jurisdiction over waters it claims as its own. The coast guard statement said the force would “firmly safeguard China’s territorial sovereignty and maritime rights and interests” and strengthen patrols in the area. Taiwan’s coast guard, which had prepositioned two of its own ships to shadow the Chinese vessels, responded by vowing to “employ all necessary measures to forcefully expel” any ships harassing its waters. Taipei has also instructed civilian vessels off the east coast to ignore any boarding and inspection demands from Chinese coast guard ships, with its own forces ready to intervene. Western capitals, including Washington, Paris, Berlin and London, have voiced alarm over the escalation.

Analysts in Taipei describe the coast guard deployments as “lawfare” — a strategy to establish a legal and operational precedent for Chinese jurisdiction without triggering a military confrontation. The Chinese Ministry of Natural Resources reinforced this approach on Thursday by publishing an English-language “legal opinion” asserting that Japan and the Philippines should negotiate maritime boundaries with Beijing, not with Taiwan, and that other states should refrain from assisting Tokyo and Manila. According to the document, the boundary talks involve what China considers its own waters off Taiwan’s east coast.

China’s military operates near Taiwan almost daily, but the use of coast guard vessels marks a shift toward grey-zone tactics that blur the line between law enforcement and military action. The first patrol in June was explicitly tied to the Japan-Philippines announcement, and the current rotation signals Beijing’s intent to maintain a persistent presence. The dispute has drawn in the United States, France, Germany and Britain, all of which have reacted to the developments.

The dossier remains active. China’s coast guard has stated it will continue to strengthen patrols in what it calls its jurisdictional waters, while Taiwan’s coast guard has prepositioned vessels for monitoring. No date has been set for the next rotation, but the pattern indicates continued deployments. The Japan-Philippines boundary talks, which Beijing views as involving its own claims, are expected to proceed, keeping the issue alive.