Tokyo is the largest city in Japan, forming its own administrative subdivision with a population of over 13 million. Its metropolitan area, around Tokyo Bay, has over 40 million inhabitants, making it the largest urban area in the world. Formerly named Edo, it replaced Kyoto as the country's capital in 1868. and has grown extremely rapidly ever since, in spite of sustaining massive damage during World War II.
Tokyo is located on the southern side of Honshu Island, the largest island in the Japanese archipelago, on the western shore of Tokyo Bay, an inlet of the Pacific Ocean. the cities of Kawasaki and Yokohama are located to the south, and Chiba is across the bay, to the east.
Tokyo Prefecture comprises 23 separate districts which function as independent cities; together, they cover the territory of pre-1943 Tokyo. These include:
In addition, there are 26 cities in the prefecture which lie to the west of the old Tokyo city limits.