Keian (慶安) was a Japanese era name (年号,, nengō,; lit. "year name") after Shōhō and before Jōō. This period started in February 1648 and ended in September 1652. During this time, the emperor was Go-Kōmyō-tennō (後光明天皇).
Events of the Keian era
Nihon Ōdai Ichiran was first published in the 5th year of Keian
1648 (Keian 1): Legal code about city life and business are established in Osaka
1649 (Keian 2): Five-storied pagoda at Sensō-ji (金龍山浅草寺, Kinryū-zan Sensō-ji) was built in Asakusa.
1649 (Keian 2): Legal code for peasants established by Tokugawa Iemitsu.
1 April 1649 (Keian 2, 20th day of the 2nd month): There was a major earthquake in Edo.
1651 (Keian 4): Plot to overthrow the Tokugawa, also known as the Keian Uprising.
1652 (Keian 5, 5th month): Nihon Odai Ichiran was published. The French version of this work was the first Japanese history book to be published in the West.
♯The Northern pretenders did not recognize the Genkō era. Gentoku was used in the Northern Court until 1332. ₪The Shōkyō era was recognized only by the Northern pretenders, not by the Southern Court. ‡ Upon reunification of the Northern and Southern Courts in 1392, Genchū was discontinued. Meitoku was used until 1394.