The Japanese government is buying uninhabited Mageshima Island, an abandoned outcrop 34 kilometers from the southernmost Japanese main islands (specifically Kyushu), for $146 million. Japan plans to turn the island into an airbase for use by Japanese and American military aircraft. Mageshima is 8.2 square kilometers (3.2 square miles) of flat terrain that consists of volcanic rock. It is on the edge of the East China Sea and actually part of the larger Osumi Islands. Several of the Osumis are inhabited but the fact that Mageshima is not is the main reason for using it as an airbase.
There have been several efforts to develop an economy on Mageshima but all have failed and the last resident left in 1980. One of the development projects led to the construction of two unpaved airstrips. One is 4,100 meters long down the length of the island and the other is 2,200 meters across at its widest point. The highest elevation on the island is 71 meters which is why it has been described as an unsinkable aircraft carrier. The Japanese have no plans to go that far but intend to pave the two existing airstrips and add some aircraft support facilities so the island can serve as an emergency airbase as well as a training facility. Mageshima makes it easier for U.S. naval aviators based on Okinawa to train. These carrier pilots often conduct touch and go practice landings on land bases when their carrier is not available. This causes complaints from local civilians because of the noise. To avoid those complaints the aircraft fly 1,360 kilometers to Iwo Jima to do it. With paved airstrips, along with air traffic control and other airbase facilities, the American carrier pilots only have to fly 400 kilometers to reach Mageshima to do it. These airbase facilities would also serve as a dispersal area for American and Japanese aircraft if there was a threat of war with China. Currently, all American aircraft in Japan are located at six bases, which are within range of Chinese ballistic missiles. So is Mageshima, but it would mean one more base the Chinese would have to worry about.
For Japan, a Mageshima base would make it easier to defend the Senkaku Islands 900 kilometers to the southwest. The Japanese have purchased American V-22 transports to quickly get troops to the Senkakus in case China attempts to occupy one or more of the small islands. The Mageshima airbase would prove useful for that.
The Senkakus are claimed by Japan, China and Taiwan. Japan has occupied them for over a century and currently controls the islands. During the last decade, Chinese warships have frequently entered Japanese territorial waters (within 22 kilometers of shore) around the Senkakus. China and Japan have been squabbling over ownership of the uninhabited Senkaku Islands in the East China Sea with increasing fervor. These islands are not flat and only occupied during the fishing season by crews of fishing boats. In 2005 Japanese officials took control of a privately owned lighthouse built on one of the eight small islands, and warned China to stay away. The Senkakus are actually islets, which are 167 kilometers northeast of Taiwan and 426 kilometers southeast of Japan's Okinawa and have a total area of 6.3 square kilometers. Taiwan also claims the Senkakus, which were discovered by Chinese fishermen in the 16th century, and taken over by Japan in 1879. They are valuable now because of the 380 kilometer economic zone nations can claim as their coastal waters. This includes fishing and possible underwater oil and gas fields. A conservative Japanese political group built the lighthouse in 1986, to further claims of Japanese ownership. Currently, the Japanese maintain naval and air patrols around the islands, backed by one of the most powerful naval forces in the region. Finally, there is the mutual defense treaty with the United States. China was long dissuaded by that, but no more and regularly sends ships to momentarily come closer than 22 kilometers to one or more of the islands.