The long arm of China's new maritime law risks causing conflict with US and Japan

A Chinese Coast Guard taskforce advances at full speed in Zhanjiang, Guangdong Province in China on August 13.

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Hong Kong (CNN)Beijing wants foreign vessels to give notice before entering "Chinese territorial waters," providing maritime authorities with detailed information -- including the ship's name, call sign, current position, next port of call and estimated time of arrival.

It may sound like a reasonable enough request, especially if the ship is carrying hazardous goods, that is until you consider what constitutes "Chinese territorial waters."
Beijing asserts sovereignty over vast swathes of the South China Sea, under its widely contested and far-reaching nine-dash line, as well as disputed islands in the East China Sea.
    Begging the question, will China try to enforce the new law in disputed seas? If it does, Pacific powers like Japan and the United States almost certainly won't comply. And in such a scenario, the question quickly becomes, how will China react?
      As of September 1, five types of foreign vessels -- submersibles, nuclear-powered vessels, ships carrying radioactive materials, ships carrying bulk oil, chemicals, liquefied gas or other toxic substances, as well the seemingly catch all "vessels that may endanger China's maritime traffic safety" -- will be required by law to provide detailed information to state authorities on entering "Chinese territorial waters," according to a notice released by China's maritime safety authorities last Friday.
      However, the regulations lack specifics and Western analysts say they skirt close to countering the United Nations Convention on the Law of the Sea, which guarantees a coastal state will not hamper the right of passage of foreign vessels if they don't threaten a nation's security.
      "This looks like part of China's strategy of casting legal nets over areas that it claims ... to 'normalize' these claims," said Robert Ward, senior fellow for Japanese security studies at The International Institute for Strategic Studies in London.
        "Enforcement will be difficult, but this may matter less for Beijing than the slow accumulation of what it sees as a legal underpinning," Ward said.
        The new regulations are the second such instance of Beijing attempting to provide a legal justification for its maritime reach this year, following a law introduced in February that allows the Chinese Coast Guard to use weapons to protect China's national sovereignty, an action previously reserved for units of the People's Liberation Army.
        The main focus of both of China's new legal claims is widely considered to be the South China Sea, almost all of which Beijing claims as its sovereign territory, despite overlapping claims by the Philippines, Vietnam, Malaysia, Brunei, Indonesia and Taiwan.
        The US Coast Guard's top commander in the Pacific, Vice Adm. Michael McAllister, on Friday called the new law "very concerning," telling CNN that if enforced, it "begins to build foundations for instability and potential conflicts" in the South China Sea.
        The US has shown a staunch unwillingness to comply with China's demands in the region, routinely carrying out freedom of navigation operations, which challenge Beijing's claims to disputed islands. During a speech in Singapore in July, US Secretary of Defense Lloyd Austin pushed back against what he described as China's illegitimate claims to the vast resource-rich waterway.