Emperor Chūai is regarded by historians as a "legendary Emperor" as there is insufficient material available for further verification and study. The lack of this information has made his very existence open to debate. There is no evidence to suggest that the title tennō was used during the time to which Chūai's reign has been assigned. It is certainly possible that he was a chieftain or local clan leader, and that the polity he ruled would have only encompassed a small portion of modern-day Japan. The name Chūai-tennō was more than likely assigned to him posthumously by later generations. His name might have been regularized centuries after the lifetime ascribed to Chūai, possibly during the time in which legends about the origins of the Yamato dynasty were compiled as the chronicles known today as the Kojiki.
