Tokyo (東京, Tōkyō; "Eastern Capital"^?), officially Tokyo Metropolis (東京都, Tōkyō-to^?), is the capital and largest city of Japan, and is one of the 47 prefectures of Japan. It is located on the eastern side of the main island Honshū. Tokyo's government also administers the twenty-three special wards of Tokyo, each governed as a city, that cover the area that was once the city of Tokyo in the eastern part of the prefecture.

The population of the special wards is over 8 million people, with the total population of the prefecture exceeding 12 million. The prefecture is the center of the Greater Tokyo Area, 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.