Empress Kōken (孝謙天皇 Kōken-tennō), also known as Empress Shōtoku (称徳天皇 Shōtoku-tennō), was the 46th (with Empress Kōken name) and the 48th monarch of Japan (with Empress Shōtoku name), according to the traditional order of succession.
Empress Kōken first reigned from 749 to 758. Then, following the Fujiwara no Nakamaro Rebellion, she reascended the throne as Empress Shōtoku from 765 until her death in 770.
Empress Kōken was involved in the Rasputin-like affair with priest Dōkyō and appointed him Grand Minister in 764. In 766 he was promoted to Hōō (priestly emperor) and in 770 had tried to ascend to throne by himself. The death of the Empress and the resistance of the aristocracy destroyed his plans. This incident was a reason for the later move of the Japanese capital from Nara (Heijō). In the history of Japan, Kōken/Shōtoku was the sixth of eight women to take on the role of empress regnant. The five female monarchs before Kōken/Shōtoku were Suiko, Kōgyoku/Saimei, Jitō, Gemmei and Genshō; and the two women sovereigns reigning after Kōken/Shōtoku were Meishō and Go-Sakuramachi.