Tokyo - one of the 47 prefectures of Japan, has served as the Japanese capital since 1869.[7][8] As of 2018, the Greater Tokyo Area ranked as the most populous metropolitan area in the world.[9]The urban area houses the seat of the Emperor of Japan, of the Japanese government and of the National Diet. Tokyo forms part of the Kantō region on the southeastern side of Japan's main island, Honshu, and includes the Izu Islands and Ogasawara Islands
