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 parts of six neighbouring prefectures, is the most-populous metropolitan area in the world, with 40.8 million residents as of 2023.

The Greater Tokyo Area is the most populous metropolitan area in the world, consisting of the Kantō region of Japan as well as the prefecture of Yamanashi of the neighboring Chūbu region. In Japanese, it is referred to by various terms, one of the most common being Capital Region .