Tokyo, officially the Tokyo Metropolis, is the capital city of Japan and one of the most populous cities in the world, with a population of over 14 million residents as of 2023. The Greater Tokyo Area, which includes Tokyo and nearby six prefectures, is th…Tokyo, officially the Tokyo Metropolis, is the capital city of Japan and one of the most populous cities in the world, with a population of over 14 million residents as of 2023. The Greater Tokyo Area, which includes Tokyo and nearby six prefectures, is the most-populous metropolitan area in the world, with 40.8 million residents as of 2023.