Tokyo , is one of the 47 prefectures of Japan. Tokyo is the capital of Japan, the center of the Greater Tokyo Area, and the largest metropolitan area of Japan. It is the seat of the Japanese government and the Imperial Palace, and the home of the Japanese Imperial Family. Tokyo is located in the Kantō region on the southeastern side of the main island Honshu and includes the Izu Islands and Ogasawara Islands. Tokyo Metropolis was formed in 1943 from the merger of the former Tokyo Prefecture (東京府, Tōkyō-fu?) and the city of Tokyo (東京市, Tōkyō-shi?).
The Tokyo Metropolitan government administers the twenty-three special wards of Tokyo (each governed as a city), which cover the area that was the city of Tokyo, as well as 39 municipalities in the western part of the prefecture and the two outlying island chains. The population of the special wards is over 8 million people, with the total population of the prefecture exceeding 13 million. The prefecture is part of the world's most populous metropolitan area with upwards of 35 million people and the world's largest metropolitan economy with a GDP of US$1.479 trillion at purchasing power parity in 2008, ahead of New York City, which ranks second on the list. The city hosts 47 of the Fortune Global 500 companies, the highest amount of any city.
Tokyo has been described as one of the three "command centers" for the world economy, along with New York City and London. This city is considered an alpha+ world city, listed by the GaWC's 2008 inventory and ranked third among global cities by Foreign Policy's 2010 Global Cities Index. In 2010 Tokyo was named the second most expensive city for expatriate employees, according to the Mercer and Economist Intelligence Unit cost-of-living surveys, and named the fourth Most Liveable City and the World’s Most Livable Megalopolis by the magazine Monocle. The Michelin Guide has awarded Tokyo by far the most Michelin stars of any city in the world. Tokyo hosted the 1964 Summer Olympics and is currently bidding to host the 2020 Summer Olympics.
Etymology
Tokyo was originally known as Edo, meaning "estuary". Its name was changed to Tokyo (Tōkyō: tō (east) + kyō (capital)) when it became the imperial capital in 1868, in line with the East Asian tradition of including the word capital ('京') in the name of the capital city. During the early Meiji period, the city was also called "Tōkei", an alternative pronunciation for the same Chinese characters representing "Tokyo". Some surviving official English documents use the spelling "Tokei". However, this pronunciation is now obsolete.
Geography and administrative divisions

The mainland portion of Tokyo lies northwest of Tokyo Bay and measures about 90 km east to west and 25 km north to south. Chiba Prefecture borders it to the east, Yamanashi to the west, Kanagawa to the south, and Saitama to the north. Mainland Tokyo is further subdivided into the special wards (occupying the eastern half) and the Tama area (多摩地域) stretching westwards.
Also within the administrative boundaries of Tokyo Metropolis are two island chains in the Pacific Ocean directly south: the Izu Islands, and the Ogasawara Islands, which stretch more than 1,000 km away from the mainland. Because of these islands and mountainous regions to the west, Tokyo's overall population density figures far underrepresent the real figures for urban and suburban regions of Tokyo.
Under Japanese law, Tokyo is designated as a to , translated as metropolis. Its administrative structure is similar to that of Japan's other prefectures. Within Tokyo lie dozens of smaller entities, including many cities, the twenty-three special wards, districts, towns, villages, a quasi-national park, and a national park. The twenty-three special wards (特別区 -ku), which until 1943 constituted the city of Tokyo, are now separate, self-governing municipalities, each having a mayor, a council, and the status of a city.
In addition to these 23 special wards, Tokyo also includes 26 more cities (市 -shi), five towns (町 -chō or machi), and eight villages (村 -son or -mura), each of which has a local government. The Tokyo Metropolitan Government is headed by a publicly elected governor and metropolitan assembly. Its headquarters are in the ward of Shinjuku. They govern all of Tokyo, including lakes, rivers, dams, farms, remote islands, and national parks in addition to its neon jungles, skyscrapers and crowded subways.
Islands
Tokyo has numerous outlying islands, which extend as far as 1850 km from central Tokyo. Because of the islands' distance from the administrative headquarters of the metropolitan government in Shinjuku, local offices administer them.
The Izu Islands are a group of volcanic islands and form part of the Fuji-Hakone-Izu National Park. The islands in order from closest to Tokyo are Izu Ōshima, Toshima, Niijima, Shikinejima, Kozushima, Miyakejima, Mikurajima, Hachijojima, and Aogashima. The Izu Islands are grouped into three subprefectures. Izu Ōshima and Hachijojima are towns. The remaining islands are six villages, with Niijima and Shikinejima forming one village.
The Ogasawara Islands include, from north to south, Chichi-jima, Nishinoshima, Haha-jima, Kita Iwo Jima, Iwo Jima, and Minami Iwo Jima. Ogasawara also administers two tiny outlying islands: Minami Torishima, the easternmost point in Japan and at 1,850 km the most distant island from central Tokyo, and Okino Torishima, the southernmost point in Japan. The last island is contested by the People's Republic of China as being only uninhabited rocks. The Iwo chain and the outlying islands have no permanent population, but host Japanese Self-Defense Forces personnel. Local populations are only found on Chichi-jima and Haha-jima. The islands form both the subprefecture of Ogasawara and the village of Ogasawara.