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 .

Ibaraki Prefecture is a prefecture of Japan located in the Kantō region of Honshu. Ibaraki Prefecture has a population of 2,828,086 and has a geographic area of 6,097.19 square kilometres. Ibaraki Prefecture borders Fukushima Prefecture to the north, Tochigi Prefecture to the northwest, Saitama Prefecture to the southwest, Chiba Prefecture to the south, and the Pacific Ocean to the east.