I think the Japanese Navy in response should sail right through so called Japanese territorial waters in the South China Sea in response to this:
The Chinese coast guard entered waters Japan claims as its territorial limit around the Senkaku Islands over the weekend, less than 10 days after Japan’s prime minister warned Tokyo would use military force if China attacked Taiwan. Four Chinese vessels crossed into the 12-mile zone east of the Senkakus around 10:15 a.m. Sunday, according to a Japan coast guard statement released the same day. The uninhabited Senkakus — five islets and three rocky outcrops — lie about 105 miles east of Taiwan and 254 miles west of Okinawa. They are administered by Japan but also claimed by China and Taiwan.
At some point the Japanese have got to give the Senkaku Islands the Dokdo treatment and just put a small military garrison on it in order to show the island is and always will be Japanese:
Japan and China are accusing each other of violating the airspace around the Japanese-controlled East China Sea islands that Beijing also claims. Japan’s Foreign Ministry issued a statement saying that it has protested to Beijing after a Chinese helicopter that took off from one of China’s four coast guard boats had entered Japan’s territorial waters around the Senkaku island, violating the Japanese airspace around them for about 15 minutes on Saturday.
In response to the airspace intrusion, Japan’s Self-Defense Force scrambled fighter jets, the Defense Ministry said. China routinely sends coast guard vessels and aircraft into waters and airspace surrounding the islands, which China calls the Diaoyu, to harass Japanese vessels in the area and force Japan to scramble jets in response.
