was a after Jōgen and before Eikan. This period spanned the years from November 978 through April 983.Nussbaum, Louis-Frédéric. (2005). "Tengen" in ; n.b., Louis-Frédéric is pseudonym of Louis-Frédéric Nussbaum, see Deutsche Nationalbibliothek Authority File . The reigning emperor was .Titsingh, Isaac. (1834). Annales des empereurs du japon, pp. 144–148; Brown, Delmer et al. (1979). Gukanshō, p. 299–300; Varely, H. Paul. (1980). Jinnō Shōtōki, pp. 191–192.
Change of era
February 20, 978 : The new era name was created to mark an event or a number of events. The previous era ended and a new one commenced in Jōgen 3, on the 15th day of the 4th month of 978.Brown, p. 300.
Events of the Tengen era 978 (Tengen 1, 8th month): The emperor allowed the daughter of Fujiwara no Kaneie to be introduced into his household; and shortly thereafter, they had a son.Titisingh, p. 146. 978 (Tengen 1, 10th month): Fujiwara no Yoritada was elevated to the position of Daijō-daijin; Minamoto no Masanobu was made Sadaijin; and, Fujiwara no Kaneie was made Udaijin.
Notes
References Brown, Delmer M. and Ichirō Ishida, eds. (1979). Gukanshō: The Future and the Past. Berkeley: University of California Press. ; OCLC 251325323 Nussbaum, Louis-Frédéric and Käthe Roth. (2005). Japan encyclopedia. Cambridge: Harvard University Press. ; OCLC 58053128 Titsingh, Isaac. (1834). Nihon Ōdai Ichiran; ou, Annales des empereurs du Japon. Paris: Royal Asiatic Society, Oriental Translation Fund of Great Britain and Ireland. OCLC 5850691 Varley, H. Paul. (1980). A Chronicle of Gods and Sovereigns: Jinnō Shōtōki of Kitabatake Chikafusa. New York: Columbia University Press. ; OCLC 6042764
External links National Diet Library, "The Japanese Calendar" -- historical overview plus illustrative images from library's collection