Tokyo, historically known in the West as Tokio and officially the Tokyo Metropolis, is the capital, the largest city, and the most populous metropolitan area in the Greater Tokyo Area, the Kantō region, and Japan, as well as the most populous metropolitan area in the world and most populous prefecture of Japan. Located at the head of Tokyo Bay, the prefecture forms part of the Kantō region on the central Pacific coast of Japan's main island of Honshu. Tokyo is the political and economic center of the country, as well as the seat of the Emperor of Japan and the national government. As of 2021, the prefecture has an estimated population of 14.04 million. The Greater Tokyo Area is the most populous metropolitan area in the world, with an estimated 37.468 million residents in 2018.