Emperor Kōshō

Kōshō is the fifth emperor (tenno) of Japan to appear on the traditional list of emperors. This posthumous name (if he ever lived) literally means "filial manifestation."

Later generations have included this name to the list of emperors (tenno) of Japan (as 孝昭天皇, Kōshō Tennō), thus making him posthumously an emperor and assigning him as one of the early sovereigns and ancestors of the dynasty that has reigned unbroken since time immemorial. If he lived, at his time the title tenno was not yet used, and the polity he possibly ruled did certainly not contain all or even the most of Japan. Concluding from his alleged successors in beginnings of historical time, also Kosho would have been a chieftain, local king, in early Yamato tribal society.

No firm date can be assigned to this monarch and he is regarded by historians as a "legendary emperor", a mythical figure. He was the fourth one of eight emperors without legend. In Kojiki and Nihonshoki only his name and genealogy were recorded.

His historical existence was believed traditionally and a tomb was attributed to him, but contemporary studies support the view that no such person existed.