Okimi

Ōkimi (大王, Ōkimi, Daiō), or Ame no shita Siroshimesu Ōkimi (治天下大王, Chi Tenka Daiō), was the title of the head of the Yamato Kingship, or the monarch title of Wakoku (Old Japan). This term was used from the Kofun period through the Asuka period in ancient Japan.

Etymology
The title 大王 (Ōkimi or Daiō), which is an honorific title for the head (king) of the Yamato Kingship, was established around the 5th century and was used until the 680s. It was established when the compilation of the Asuka Kiyomihara Code started. There are several theories upon whether the title holder in the early period is a king of the unified kingship or not. Ōkimi in Japanese reading is created by adding the prefix ō or oho, which indicates greatness and particular nobleness, to the title kimi (lord), which indicates a master or nobleman. Another theory states that Ōkimi is only an honorific form of kimi, a title with Japanese origins, while Daiō is based on a king title which originated from China; the title of kango (Chinese word).