Last week, China's state-run Global Times newspaper warned anyone drilling in the South China Sea to stop or "prepare for the sounds of cannons". Beijing's rhetoric sometimes rings hollow, but prepare for more than angry words after ExxonMobil's "potentially significant" gas discovery off Vietnam's coast announced at the weekend.
Few issues are as contentious as resource claims in international waters. Closer to home, Turkey is squaring off with Cyprus over gasfields in the Levant Basin; Lebanon and Israel have been arguing for years over other offshore gasfields in the same area.
But no country has been as explicit in its threats against its neighbours as China. And more worryingly, Beijing is able - and apparently willing - to back up its bluster.
How did it come to this? Under the 1982 Law of the Sea treaty, signatory nations were given exclusive rights to resources within 200 nautical miles of their shorelines. On paper, the scheme is sound. But in the South China Sea, competing claims over the Spratly Islands by China, Brunei, Malaysia, the Philippines, Taiwan and Vietnam have complicated matters.
Each side has, at times, stepped over the line. But China's claim to nearly the entire sea - first made in 2009 - is rooted in little more than its military advantage, which it has not been shy to exercise. From interference in oil exploration to the detention of Vietnamese fishermen, China has foregone diplomacy in favour of belligerent posturing.
Earlier this year, the Chinese navy intercepted an Indian ship leaving a Vietnamese port (the two countries have recently signed oil exploration deals). The ExxonMobil strike shows that there are significant sovereign interests at stake; Vietnam's ailing energy sector desperately needs the resources that are, after all, within its 200-mile zone.
There are diplomatic solutions being pursued. The Association of Southeast Asian Nations (Asean) is working to finalise a joint statement on China's overreach. Weak on other issues, a unified Asean - backed by international law - could push Beijing much more effectively.
And while the South China Sea might be the flashpoint in this case, there are lessons for the application of the Law of the Sea more broadly. In the absence of international dispute resolution through the United Nations, these issues are viewed through the sights of a cannon. China does not seem to realise that is dangerous for everyone.