was a after Shōhō and before Jōō. This period spanned the years from February 1648 through September 1652.Nussbaum, Louis-Frédéric. (2005). "Keian" in Japan encyclopedia, p. 503; 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, p. 412.
Change of era 1648 : The new era name was created in response to criticism that Shōhō was too closely related to Shōbō (焼亡, meaning "death by burning"). The previous era ended and a new one commenced in Shōhō 5, on the 5th day of the 2nd month.
The new era name was drawn from the Chinese classic, The I Ching: "At the end happiness, joy of quiet righteousness, answer the world unlimited" (乃終有慶、安貞之吉、応地無疆):
Events of the Keian era April 1, 1649 (Keian 2, 20th day of the 2nd month): There was a major earthquake in Edo. 1651 (Keian 4): Keian Uprising. Plans by well-organized rōnin to attack several Tokugawa strongholds simultaneously were timely discovered. The attempt plan to overthrow the Edo Bakufu by Marubashi Chūya and Yui Shōsetsu was thwarted.Screech, T. (2006). Secret Memoirs of the Shogans: Isaac Titsingh and Japan, 1779–1822, pp. 85–89. 1652 (Keian 5, 5th month): Nihon Ōdai Ichiran is first published in Kyoto under the patronage of the tairō Sakai Tadakatsu, daimyō of the Obama Domain of Wakasa Province.Titsingh, p. 412; n.b., the first copy of this rare book was brought from Japan to Europe by Isaac Titsingh in 1796. Titsingh translated the text from Japanese and Chinese; and his work was then supplemented for posthumous publication by Julius Klaproth. The initial Japanese authorship is confirmed; the precise nengō-dating is confirmed in the same passage -- see Titsingh, p. 406.
Notes
References Nussbaum, Louis Frédéric and Käthe Roth. (2005). Japan Encyclopedia. Cambridge: Harvard University Press. ; OCLC 48943301 Screech, Timon. (2006). Secret Memoirs of the Shoguns: Isaac Titsingh and Japan, 1779–1822. London: RoutledgeCurzon. ; OCLC 65177072 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
External links National Diet Library, "The Japanese Calendar" -- historical overview plus illustrative images from library's collection