(444 – 484) was the 22nd (possibly legendary) emperor of Japan, according to the traditional order of succession. He is best known for events that took place before and after his reign with a void in between. These include a rebellion which was quickly put down, and a succession crisis as the Emperor had no children. Because Seinei had such a low profile, historians have questioned his existence and whether he ever ascended to the throne.
No firm dates can be assigned to this emperor's life or reign, but he is conventionally considered to have reigned from 480 to 484. Dates confirmed as "traditional" did not appear until the reign of Emperor Kanmu (the 50th emperor). Modern historians have come to the conclusion that the title of "Emperor" and the name "Seinei" were used by later generations to describe him.
Narrative
The Japanese have traditionally accepted this sovereign's historical existence, and a mausoleum (misasagi) for Seinei is currently maintained. The following information available is taken from the pseudo-historical Kojiki and Nihon Shoki, which are collectively known as or Japanese chronicles. These chronicles include legends and myths, as well as potential historical facts that have since been exaggerated and/or distorted over time. It is recorded in the Nihon Shoki that Seinei was born to sometime in 444 AD, and was given the name . Yūryaku had taken notice at how Shiraka was born with white hair as meaning something significant. While Hoshikawa was Prince Shiraka's older brother, the eldest sibling in the household () advised against it.
When word got to the Emperor about the two Princes, he was delighted and formerly adopted them as his heirs. The two debated the issue for about a year while Princess Iitoyo, a daughter of Emperor Richū was allegedly made regent.
There is no evidence to suggest that the title tennō (meaning "emperor") was used during the time to which Seinei's reign has been assigned. Instead, his title could have possibly been , meaning "the great king who rules all under heaven", or "Great King of Yamato". The name Seinei-tennō was more than likely assigned to him posthumously by later generations. His name might have been regularized centuries after the lifetime ascribed to Seinei, possibly during the time in which legends about the origins of the imperial dynasty were compiled as the chronicles known today as the Kojiki.
Outside of the Kiki, the reign of Emperor Kinmei ( – 571 AD) is the first for which contemporary historiography has been able to assign verifiable dates. The conventionally accepted names and dates of the early Emperors were not confirmed as "traditional" though, until the reign of Emperor Kanmu between 737 and 806 AD.