was a after Ryakunin and before Ninji. This period spanned the years from February 1239 to July 1240.Nussbaum, Louis-Frédéric. (2005). "En'ō" in Japan encyclopedia, p. 180; n.b., Louis-Frédéric is pseudonym of Louis-Frédéric Nussbaum, see . The reigning emperor was .Titsingh, Isaac. (1834). Annales des empereurs du Japon, pp. 242-244; Varley, H. Paul. (1980). Jinnō Shōtōki. p. 227.

Change of era 1239 : The era name was changed to mark an event or a number of events. The previous era ended and a new one commenced in Ryakunin 2.

Events of the En'ō Era 1239 (En'ō 1, 1st month): The Daijo daijin retired from worldly concerns, taking the tonsure of a Buddhist priest.Titsingh, p. 244. 1239 (En'ō 1, 2nd month): Former Emperor Go-Toba died at age 60.

Notes

References Nussbaum, Louis-Frédéric and Käthe Roth. (2005). Japan encyclopedia. Cambridge: Harvard University Press. ; OCLC 58053128 Titsingh, Isaac. (1834). Nihon Odai 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