China and the Philippines have again exchanged accusations over their competing claims in the South China Sea, the Associated Press reported on Thursday.

Exchanges of this kind happen frequently enough that they rarely hold international attention for long. That regularity is itself the thing worth explaining.

What is actually being claimed

China asserts rights over most of the South China Sea on historical grounds, marked on its maps by a line enclosing waters that reach close to the coastlines of several neighbours.

The Philippines, along with Vietnam, Malaysia, Brunei and Taiwan, claims portions based on the UN Convention on the Law of the Sea, under which a coastal state has an exclusive economic zone extending 200 nautical miles from its shore.

In 2016 an arbitral tribunal constituted under that convention ruled substantially in favour of the Philippines, finding no legal basis for China’s historic rights claim within the line. China did not participate in the proceedings and rejects the award.

That is the structural problem. There is a binding ruling and no mechanism to enforce it, which is a recurring feature of international adjudication — and the same difficulty facing the Guyana–Venezuela case we reported on yesterday.

Why it is fishing boats rather than warships

Confrontations in these waters typically involve coast guard vessels, maritime militia and fishing fleets rather than navies, and that is deliberate on all sides.

Analysts call it grey-zone activity: pressure applied below the threshold that would trigger a military response or invoke a defence treaty. Water cannon, blocking manoeuvres and swarming with civilian-flagged vessels achieve presence and control without producing an armed attack.

For the Philippines this matters because of its mutual defence treaty with the United States. Washington has stated the treaty covers armed attacks on Philippine public vessels in the South China Sea. A collision involving a coast guard cutter sits awkwardly against that language, which is precisely why the tactics stay where they are.

What is at stake materially

Three things, in roughly this order of practical importance.

Fisheries. The South China Sea supplies a large share of the protein consumed across the region, and stocks are under severe pressure. For coastal communities the dispute is about whether they can fish where their families always have.

Shipping. A very large proportion of global seaborne trade passes through, which is why states far from the region take positions on freedom of navigation.

Hydrocarbons. Estimated oil and gas reserves are frequently cited, but the estimates vary widely and exploration is constrained by the dispute itself. This element is probably over-weighted in coverage relative to fish.

How to read these exchanges

Both governments issue accounts of each incident, and the accounts routinely contradict each other on who manoeuvred into whom. Video released by either side is partial and begins when the releasing party chooses.

What can usually be established is location, and location is the substantive question: whether an incident occurred inside the Philippine exclusive economic zone, near a specific feature, or in waters both claim.

What is generally not resolvable from public material is fault in a particular collision. Readers encountering a confident account of who was to blame should note which government supplied the footage.

Sources

• Associated Press, China and Philippines spar over South China Sea claims, via Asahi Shimbun, 10 September 2026, listed in ISEAS Daily News on Southeast Asia
• Award of the Arbitral Tribunal in the South China Sea Arbitration (Philippines v. China), 12 July 2016
• United Nations Convention on the Law of the Sea, provisions on exclusive economic zones
• Published analysis of grey-zone maritime activity and coast guard tactics