is one of the 47 prefectures of Japan. It includes the highly urbanized central area, which was formerly the city of Tokyo and is still popularly known by this name, now administered as 23 separate cities — the 23 special wards. Prior to 1943, Tokyo was the name of both the prefecture and the city. In 1943 the Tokyo city government was dissolved and, since then, the prefecture has been the only government having the name Tokyo. In recognition of its special status, Tokyo is the only prefecture designated in Japanese as a .
Although not a single city, the Tokyo metropolis is home to the Japanese government and emperor. and is considered to be the capital of Japan. About 12 million people—10 percent of the country's population—live in Tokyo, while about 33–36 million people live in the entire Greater Tokyo area, making it part of the most populated urban area on Earth.