officially , is one of the 47 prefectures of Japan. Tokyo is the capital of Japan, the center of the Greater Tokyo Area, and the most populous metropolitan area in the world. It is the seat of the Emperor of Japan and the Japanese government. Tokyo is in the Kantō region on the southeastern side of the main island Honshu and includes the Izu Islands and Ogasawara Islands. Formerly known as Edo it has been the de facto seat of government since 1603 when Shogun Tokugawa Ieyasu made the city his headquarter but only became the capital and was renamed Tokyo after Emperor Meiji moved his seat to the city from the old capital of Kyoto in 1868. Tokyo Metropolis was formed in 1943 from the merger of the former and the .
Tokyo is often referred to and thought of as a city, but is officially known and governed as a "metropolitan prefecture", which differs from and combines elements of both a city and a prefecture; a characteristic unique to Tokyo. The Tokyo metropolitan government administers the 23 Special Wards of Tokyo (each governed as an individual city), which cover the area that was formerly the City of Tokyo before it merged and became the subsequent metropolitan prefecture in 1943. The metropolitan government also administers 39 municipalities in the western part of the prefecture and the two outlying island chains. The population of the special wards is over 9 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 37.8 million people and the world's largest urban agglomeration economy. The city hosts 51 of the Fortune Global 500 companies, the highest number of any city. The city is also home of various television networks like Fuji TV and the Tokyo Broadcasting System.
The city is considered an alpha+ world city—as listed by the GaWC's 2008 inventory—and in 2014, Tokyo was ranked first in the "Best overall experience" category of TripAdvisor's World City Survey (the city also ranked first in the following categories: "Helpfulness of locals", "Nightlife", "Shopping", "Local public transportation" and "Cleanliness of streets"). In 2013, Tokyo was named the third most expensive city for expatriates, according to the Mercer consulting firm, and the world's most expensive city, according to the Economist Intelligence Unit's cost-of-living survey. In 2009 Tokyo was named the third Most Liveable City by the magazine Monocle. The Michelin Guide has awarded Tokyo by far the most Michelin stars of any city in the world.
Tōkyō is a prefecture and city.