Tokyo (東京,),  is one of the 47 prefectures of Japan. It is located on the eastern side of the main island Honshū and includes the Izu Islands and Ogasawara Islands. Tokyo Metropolis was formed in 1943 from the merger of the former Tokyo Prefecture and the city of Tokyo.

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.

The Tokyo Metropolitan government administers the twenty-three special wards of Tokyo, each governed as a city, that 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 35 to 39 million people (depending on definition) and the world's largest metropolitan economy with a GDP of US$1.479 trillion at purchasing power parity in 2008, surpassing even New York City, which ranks second on the list.

Tokyo was described by Saskia Sassen 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 2009 Tokyo was named the world's most expensive city for expatriate employees, according to the Mercer and Economist Intelligence Unit cost-of-living surveys  and named the third Most Liveable City and the World’s Most Livable Megalopolis by the magazine Monocle.

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.

Tokyo Metropolitan Government Building.

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 (都), 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.

National parks

There are several national parks within Tokyo, among them:

• Meiji no Mori Takao Quasi-National Park, around Mount Takao to the south of Hachiōji
• Ogasawara National Park. As of 2006, efforts were being made to make Ogasawara National Park a UNESCO natural World Heritage Site.
• Ueno Park, well known for its museums: Tokyo National Museum, National Science Museum, Shitamachi Museum and National Museum for Western Art, among others. There are also art works and statues at several places in the park.

Seismicity

Tokyo was hit by powerful earthquakes in 1703, 1782, 1812, 1855 and 1923. The 1923 earthquake, with an estimated magnitude of 8.3, killed 142,000 people. Tokyo is located near the boundary of three plates that have been relatively quiet since 1923, it is thought that this shows that the seismic activity is building up and will surely release in a devastating earthquake some time in the future. Even if this was not as powerful as the 1923 earthquake, its damage would be far greater because of the massive expansion after World War II.

Climate

The former city of Tokyo and the majority of mainland Tokyo lie in the humid subtropical climate zone (Koppen climate classification Cfa), with hot humid summers and generally mild winters with cool spells. The region, like much of Japan, experiences a one-month seasonal lag, with the warmest month being August, which averages 27.5 °C (81.5 °F), and the coolest month being January, averaging 6.0 °C (42.8 °F). Annual rainfall averages nearly 1,470 millimetres (57.9 in), with a wetter summer and a drier winter. Snowfall is sporadic, but does occur almost annually. Tokyo also often sees typhoons each year, though few are strong. The last one to hit was Fitow in 2007.

Demographics

As of October 2007, the official intercensal estimate showed 12.79 million people in Tokyo with 8.653 million living within Tokyo's 23 wards. During the daytime, the population swells by over 2.5 million as workers and students commute from adjacent areas. This effect is even more pronounced in the three central wards of Chiyoda, Chūō, and Minato, whose collective population as of the 2005 National Census was 326,000 at night, but 2.4 million during the day.

The entire prefecture had 12,790,000 residents in October 2007 (8,653,000 in 23 wards), with an increase of over 3 million in the day. Tokyo is at its highest population ever, while that of the 23 wards peak official count was 8,893,094 in the 1965 Census, with the count dipping below 8 million in the 1995 Census. People continue to move back into the core city as land prices have fallen dramatically.

As of 2005, the most common foreign nationalities found in Tokyo are Chinese (123,661), Korean (106,697), Filipino (31,077), American (18,848), British (7,696), Brazilian (5,300) and French (3,000).

The 1889 Census recorded 1,389,600 people in Tokyo City, Japan's largest city at the time.

Economy

Tokyo Stock Exchange, the second largest in the world by market capitalization.

Bank of Japan.

Shiodome City Center in Minato, headquarters of All Nippon Airways and Fujitsu.

Mitsubishi CorporationMarunouchi, Chiyoda.

Tokyo is one of the three world finance "command centers", along with New York City and London. Tokyo has the largest metropolitan economy in the world. According to a study conducted by PricewaterhouseCoopers, the Tokyo urban area (35.2 million people) had a total GDP of US$1.479 trillion in 2008 (at purchasing power parity), which topped the list. As of 2009, 51 of the companies listed on the Global 500 are based in Tokyo, almost twice that of the second-placed city (Paris).

Tokyo is a major international finance center, houses the headquarters of several of the world's largest investment banks and insurance companies, and serves as a hub for Japan's transportation, publishing, and broadcasting industries. During the centralized growth of Japan's economy following World War II, many large firms moved their headquarters from cities such as Osaka (the historical commercial capital) to Tokyo, in an attempt to take advantage of better access to the government. This trend has begun to slow due to ongoing population growth in Tokyo and the high cost of living there.

Tokyo was rated by the Economist Intelligence Unit as the most expensive (highest cost-of-living) city in the world for 14 years in a row ending in 2006. This analysis is for living a corporate executive lifestyle, with items like a detached house and several automobiles.

The Tokyo Stock Exchange is Japan's largest stock exchange, and second largest in the world by market capitalization and fourth largest by share turnover. In 1990 at the end of the Japanese asset price bubble, it accounted for more than 60% of the world stock market value. Tokyo had 8,460 ha (20,900 acres) of agricultural land as of 2003, according to the Ministry of Agriculture, Forestry and Fisheries, placing it last among the nation's prefectures. The farmland is concentrated in Western Tokyo. Perishables such as vegetables, fruits, and flowers can be conveniently shipped to the markets in the eastern part of the prefecture. Japanese leaf spinach and spinach are the most important vegetables; as of 2000, Tokyo supplied 32.5% of the Japanese leaf spinach sold at its central produce market.

With 36% of its area covered by forest, Tokyo has extensive growths of cryptomeria and Japanese cypress, especially in the mountainous western communities of Akiruno, Ōme, Okutama, Hachiōji, Hinode, and Hinohara. Decreases in the price of lumber, increases in the cost of production, and advancing old age among the forestry population have resulted in a decline in Tokyo's output. In addition, pollen, especially from cryptomeria, is a major allergen for the nearby population centers.

Tokyo Bay was once a major source of fish. Presently, most of Tokyo's fish production comes from the outer islands, such as Izu Ōshima and Hachijōjima. Skipjack tuna, nori, and aji are among the ocean products.

Tourism in Tokyo is also a contributor to the economy.

Transportation

Map of Tokyo Subway system.

Tokyo, as the center of the Greater Tokyo Area, is Japan's largest domestic and international hub for rail, ground, and air transportation. Public transportation within Tokyo is dominated by an extensive network of clean and efficient trains and subways run by a variety of operators, with buses, monorails and trams playing a secondary feeder role.

Within Ōta, one of the 23 special wards, Haneda Airport offers domestic and international flights. Outside Tokyo, Narita International Airport, in Chiba Prefecture, is the major gateway for international travelers to Japan and Japan`s flag carrier Japan Airlines, All Nippon Airways, Delta Air Lines, and United Airlines all have a hub at this airport.

Various islands governed by Tokyo have their own airports. Hachijōjima (Hachijojima Airport), Miyakejima (Miyakejima Airport), and Izu Ōshima (Oshima Airport) have service to Tokyo International and other airports.

Rail is the primary mode of transportation in Tokyo, which has the most extensive urban railway network in the world and an equally extensive network of surface lines. JR East operates Tokyo's largest railway network, including the Yamanote Line loop that circles the center of downtown Tokyo. Two organizations operate the subway network: the private Tokyo Metro and the governmental Tokyo Metropolitan Bureau of Transportation. The metropolitan government and private carriers operate bus routes. Local, regional, and national services are available, with major terminals at the giant railroad stations, including Tokyo, Shinagawa, and Shinjuku.

Expressways link the capital to other points in the Greater Tokyo area, the Kantō region, and the islands of Kyūshū and Shikoku.

Other transportation includes taxis operating in the special wards and the cities and towns. Also long-distance ferries serve the islands of Tokyo and carry passengers and cargo to domestic and foreign ports.

Cityscape

Architecture in Tokyo has largely been shaped by Tokyo's history. Twice in recent history has the metropolis been left in ruins: first in the 1923 Great Kantō earthquake and later after extensive firebombing in World War II. Because of this, Tokyo's current urban landscape is one of modern and contemporary architecture, and older buildings are scarce.

Tokyo also contains numerous parks and gardens.

Panoramic view of Shinjuku and Mount Fuji taken from Bunkyo Civic Center

Panoramic view of Tokyo Imperial Palace as seen from Marunouchi

Sakura in Tokyo Imperial Palace

Portion of city from the Tokyo Imperial Palace.