April 15, 2010:  Japan reports that, for the third time in the past 18 months, Chinese warships have been spotted south of the Japanese Island of Okinawa. This time, it was two Chinese submarines, running on the surface. That had never been seen before, in the area near the Senkaku islands (which are claimed by China, Taiwan and Japan). The Senkakus are eight uninhabited islands, which in the past were only used occasionally by fishermen. The Senkakus are 220 kilometers from Taiwan, 360 kilometers from China and 360 kilometers from Okinawa (which is part of Japan). Japan's claim is the strongest, having first been formally made in 1895. The United States took control of the islands after World War II, and used some of them for bombing practice. Japan continued to claim ownership when, in the 1970s, the possibility of oil deposits in the area caused China and Taiwan to make claims as well. The new Japanese radar facility on nearby Miyako island makes it easier for Japan to assert control over the Senkakus if there is ever a military confrontation with China.

There have been confrontations. Last year, two Chinese J-10A chased away three Japanese F-2 fighters that were near the Senkakus. Two years ago, Chinese coast guard ships began patrolling in the Senkakus, along with Chinese J-10A fighters.

Five years ago, a Chinese oil drilling platform, in disputed waters halfway between China and the Japanese island of Okinawa, began producing natural gas, despite ongoing negotiations over who owns what in that patch of ocean. The Chinese spent two years building that platform, in waters claimed by Japan. A second platform was later built, as well as an underwater oil pipeline for both platforms. China regularly sends groups of warships to patrol the area, to underline their belief that this bit of water is under Chinese control. Japan would probably win any naval war with China, but since China has nuclear weapons, and Japan does not (at least not right now), such a war could go seriously against Japan. This has been brought up in Japan before, and it is feared that the issue may lead to Japan secretly, or openly, building nuclear weapons (which it could certainly do, and quite quickly.)