The ambiguity of China's claims in the South China Sea has long been the main obstacle to resolving or even managing the jurisdictional disputes there. Despite of repeated requests from rival claimants, as well as the US, China has declined to clarify exactly what it claims and why. Its infamous nine-dash line encompassing most of the South China Sea is open to several interpretations. Persistent questioners may want to be careful what they wish for; they may not like the answer. Indeed, the recent "revision" of Hainan's fisheries regulations, which became effective on January 1, may have brought us closer to a clarification of China's claims. China is now facing a political dilemma of its own making … This seems a no-win situation The Philippines, Vietnam, the US, Japan and even Taiwan have protested. Some analysts say the revised rules violate the 2002 Asean-China Declaration on the Conduct of Parties in the South China Sea and undermine the advances made by President Xi Jinping and Premier Li Kaqiang during their "goodwill" visits to Southeast Asia last year. However, according to Taylor Fravel of MIT, these rules are not new but simply Hainan's implementation of China's 2004 fisheries law, and similar rules issued in 1993 and 1998. The concerns focus on one article in the Hainan People's Congress reaffirmation of these laws, which states that "foreigners or foreign fishing ships entering sea areas administered by Hainan and engaged in fishery production or fishery resource surveys should receive approval from relevant departments of the State Council". The problem is that the previous versions of the law specified Hainan's jurisdiction as including much of the South China Sea which is also claimed in part by Brunei, Malaysia, the Philippines, Vietnam and Taiwan. Xinhua reported that these rules apply to 2 million square kilometres in the South China Sea. Moreover, existing Chinese law stipulates that a foreign fishing vessel that enters these waters without permission will be expelled and have its catch confiscated, and be fined up to 500,000 yuan (HK$636,000). Foreign Ministry spokeswoman Hua Chunying said the regulations were "according to international law". However, the critical questions now are if, when and where the revised rules will be enforced. Some believe enforcement will be selective depending on the warmth or coolness of the flag-state's bilateral relations with China. Lin Yun, director of legal affairs for the Hainan Department of Ocean and Fisheries, implied that enforcement would be difficult given the sheer size of the area to which it applies and China's present limited enforcement capabilities. Moreover, the rules are likely to be ignored en masse by other claimants to the area so there would probably be many "offenders". Indeed, the Philippines has said it will not recognise the legislation. These regulations may not be new or articulate new policy but they do beg the questions, why now, and why has China made an in-your-face reaffirmation of such a highly controversial provision? Doing so plays right into US attempts to convince members of the Association of Southeast Asian Nations that a rising China is a threat. It also unnecessarily brings back into play the issue of "freedom of navigation" which concerns all seafaring nations. US Ambassador to the Philippines Philip Goldberg has reiterated the US concern with this principle. And China's declaration will almost certainly be used to bolster the Philippines' case against China at the International Tribunal for the Law of the Sea. But this is all theoretical unless or until China actually tries to enforce these regulations against claimants in their own claimed exclusive economic zones, or in what others claim are "high seas", where no country can make a claim. However, Vietnam and the Philippines say China has been doing so already against their vessels. If this becomes widespread and commonplace, it will indeed be - in the words of the US State Department - "provocative and potentially dangerous". China is now facing a political dilemma of its own making. If it clarifies that the law applies to much of the South China Sea and tries to enforce it, Beijing will have "crossed the Rubicon" vis-à-vis other claimants and users of the sea. If it continues its ambiguity, other nations will ignore the regulations and Chinese nationalists will claim it appears to be a "paper tiger" incapable of enforcing its own law. Domestic pressure will build for it to do so. This seems a no-win situation. To escape this conundrum, China could clarify that it claims only the disputed islands and their exclusive economic zones, and that boundaries in the South China Sea should be negotiated. Meanwhile, it should refrain from enforcing the rules beyond its own claimed exclusive economic zone and especially in other countries' claimed zones. To do otherwise is almost certain to court conflict. Mark Valencia is an adjunct research associate at the National Institute for South China Sea Studies