was a after Gennin and before Antei. This period spanned the years from April 1225 to December 1227. The reigning emperor was .
Change of era
- 1225 : The era name was changed to mark an event or a number of events. The previous era ended and a new one commenced in Gennin 2.
Events of the Karoku Era
- 1225 (Karoku 1, 11th month): At Kamakura, Kujō Yoritsune's coming of age ceremonies took place at age 8; but control of all bakufu affairs remained entirely in the hands of Hōjō Yasutoki, the regent (shikken).
- 1225 (Karoku 1, 12th month): Emperor Go-Horikawa went in formal procession to Iwashimizu Hachiman-gū and to the Kamo Shrines.