thumb|220px|Map of Okinotori

, or Parece Vela, is a coral reef, geologically an atoll, with two rocks enlarged with tetrapod-cement structures. It is administered by Japan with a total shoal area of and land area . Its dry land area is mostly made up by three concrete encasings and there is a stilt platform in the lagoon housing a research station. There is a third completely artificial tetrapod-cement islet.

Okinotori is located on the Palau–Kyushu Ridge in the Philippine Sea, southeast of Okidaitōjima and west-southwest of South Iwo Jima in the Bonin Islands or south of Tokyo, Japan. Okinotori is the southernmost part of Japan and the only Japanese territory south of the Tropic of Cancer.

Japan argues that Okinotori is significant enough for it to claim a exclusive economic zone (EEZ) around it, but China, South Korea, and Taiwan dispute the Japanese EEZ, saying that the atoll does not meet the definition of an island under the United Nations Convention on the Law of the Sea.

History

The atoll may have been sighted first by Spanish sailor Bernardo de la Torre in 1543, (Spanish for "looks like a sail", alluding to the original appearance of the reef). This name has been retained in English as well, especially to designate the geological formations of the islets.

In 1789, Captain William Douglas arrived with the British ship Iphigenia and, in 1790, the place was named Douglas Reef (also spelled Douglass Reef). This name continues to appear in modern sources. In 1796, what was likely the reef was then re-discovered by the brig Nautilus, under the command of Captain Charles Bishop, and the name Nautilus Rocks has appeared in some sources.

The existence of the atoll might not have been known by the Japanese until 1888. In 1922 and 1925, the Japanese navy ship Manshu investigated the area.

Between 1987 and 1993 the government of Tokyo and later the central government built steel breakwaters and concrete walls to stop the erosion of Okinotori, which today leaves only three of the five rocks that were present in 1939 above water; in 1988 the Japan Marine Science and Technology Center built a marine investigation facility which it has since maintained following typhoon damage. The facility also doubles as an EEZ observation post for the Maritime Bureau of the Ministry of Land, Infrastructure, Transport and Tourism, being equipped with radar and various other sensors to help monitor activity in the zone. The Parece Vela Basin contains the longest megamullion in the world. The original Spanish name of the islets is normally used for the geological formations, hence, Parece Vela megamullion, Parece Vela ridge, or Parece Vela basin.

The waters around the reefs are potentially rich in oil and other mineral and fisheries resources and it lies in an area of potential military significance. At high tide, one area of the reef is , roughly the size of a twin bed, and pokes just out of the ocean. The other is , the size of a small bedroom, and rises , about twice as high. The entire reef consists of approximately , most of which is submerged even at low tide.

The area has three tiny individual islets:

  • Higashi-Kojima (東小島, "Eastern Islet")
  • Kita-Kojima (北小島, "Northern Islet"), nevertheless rather in the "West"
  • Minami-Kojima (南小島, "Southern Islet")

thumb|220px|Satellite Image

Minami-Kojima is a completely artificial islet created in shallow water. But also the two original islets appear completely artificial today, with little if any trace of the two natural rocks that still appear on photographs of 1987. In 1925, there were still five above-water rocks, which have eroded since. A report from 1947 mentions five above-water rocks. Three smaller ones were on the west side, nearly impossible to see from seaward because of the breaking waves. The larger rocks on the southwest side and on the northeast side, possibly Kita-Kojima and Higashi-Kojima, were reported to be high, respectively. The original rocks appeared barren, without any terrestrial vegetation. The current artificial dry land areas with their concrete surfaces appear unfit to support terrestrial vegetation either.

After concrete encasing, each of the islets appears as a circle with a diameter of 60 meters (196 ft) on detailed satellite images, which would correspond to a land area—albeit mostly artificial—of per islet, or in total. In addition, there is a platform on stilts in the shallow part of the lagoon east-northeast of the southern islet, built by the Japan Marine Science and Technology Center in 1988, which appears as a rectangle of . The platform has a helicopter landing pad and a large three-story building with a marine investigation facility and a meteorological station.

The rocks are in the western part of a lagoon surrounded by a submerged coral reef, over which the waves break, and that extends east-west and north-south, with an area of roughly 5&nbsp;km<sup>2</sup> within the rim of the reef. The lagoon is 3 to 4.6 meters deep, but there are numerous coral heads of lesser depths throughout the area. The fringing reef of the atoll is pear-shaped in an east–west direction with its greatest width at the eastern end. There is a small boat channel into the lagoon in the southwest, about wide and deep, southeast of the artificial islet.

Administration

Administratively, the island is considered part of Ogasawara village, Tokyo. In 1939, the construction of a naval base was started by Japan, but suspended in 1941, at the start of the Pacific War.

Typhoons are constant threats to Okinotori's existence. In the 1970s there were about five or six visible protrusions, but by 1989, only two were visible.

Furthermore, the Nippon Foundation has drawn plans to build a lighthouse and increase the size of the reef by breeding microorganisms known as foraminifera. Creating land using the microorganisms could take decades to a century before the island is large enough to be useful.

Currently, Japan carries out maritime research and observation of the area, as well as repair work on the embankment.

In 2005, the government installed a radar system (at the cost of ¥ 330 million),

On 22 April 2004, Chinese diplomats stated during bilateral talks with Japan that they regarded Okinotori as an atoll, not an islet, and did not acknowledge Japan's claim to an EEZ stemming from Okinotori. Neither China nor South Korea have territorial claims regarding Okinotori, but foreign policy analysts speculated that they want to "investigate the surrounding seabed for submarine operations in case of military conflict involving the Republic of China (Taiwan)." Japan claims that rock is not defined in the convention. The construction of a port, lighthouse, and power station may be used as a counterargument for China's claim regarding "sustain[ing] human habitation or economic life"

The territory lies at a militarily strategic point, midway between Taiwan and Guam, the latter where U.S. forces are based. Vessels of the PRC are believed to have been mapping the ocean's bottom over which U.S. warships might pass on their way to Taiwan. The PRC conducted four maritime surveys near the Okinotori coral reefs in 2001, two in 2002, and one in 2003. However, the number of such incidents rose to four in 2004. These incidents have drawn protests from Japan. Tadao Kuribayashi, another law professor, disagrees, arguing in part that rocks and reefs differ in composition and structure, and that the intent of the provision was geared toward the former.

In 2016, Japan's arrest of a Taiwanese fishing ship's crew led Taiwan to protest against Japan's claim of island status for Okinotori and by extension the EEZ.

See also

  • Scarborough Shoal, another larger shoal with two skerries
  • Hateruma
  • Geography of Japan
  • Japanese Archipelago
  • List of extreme points of Japan
  • Territorial disputes of Japan
  • Desert island
  • List of islands
  • Farallon de Pajaros

References

  • Page with overhead photograph of the entire atoll
  • report about appearance in 1947 (under the name Parece Vela/Douglas Reef)
  • close-up photo of Higashikojima (東小島, "Eastern Islet")
  • page with photograph of platform
  • Italian page with history in English and oblique aerial photograph of Okinotori from southwest
  • detailed satellite images
  • Japanese map
  • Tokyo governor stirs reef dispute
  • Related treaties
  • Treaty of San Francisco
  • Agreement between Japan and the United States of America Concerning Nanpo Shoto and Other Islands (1968)
  • "United States Treaties and Other International Agreements VOLUME 19 IN SIX PARTS Part 4 1968" P.4895-