is a coral reef 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 complete artificial tetrapod-cement islet. It 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. The atoll is the southernmost part of Japan and the only Japanese territory in the tropics.