In 57, a chieftain of Wanonanokuni (small country in Hakata area of Fukuoka Prefecture), which is believed to have been located along the Hakata Bay, had suzerain-vassal relationship with the Emperor Kobu-tei (Emperor Guangwu) of the Latter Han Dynasty, who invested him with Wakoku by giving golden stamp (Wa no na no kokuo in [the oldest known seal in Japan]), ("History of the Latter Han Dynasty"), therefore, the center of Japanese political force is believed to have been located in the northern part of Kyushu at that time.
建武中元二年（57年）、博多湾沿岸に所在したと見られる倭奴国の首長が、後漢の光武帝から倭奴国王に冊封されて金印（倭奴国王印）の賜与を受けており（『後漢書』「」）、当時は北部九州の勢力が倭国内の中心勢力であったと考えられている。