K-On! (けいおん! Keion!?) is a Japanese four-panel comic strip manga written and illustrated by Kakifly. The manga started serialization in Houbunsha's seinen manga magazine Manga Time Kirara since the May 2007 issue, and also started a bimonthly serialization in Houbunsha's magazine Manga Time Kirara Carat since the October 2008 issue. A thirteen-episode anime adaptation produced by Kyoto Animation aired in Japan between April and June 2009. An additional original video animation episode was released in January 2010. A second season, titled K-On!! (with two exclamation marks), began airing in Japan from April 7, 2010. The title of the series comes from the Japanese word for light music, keiongaku (軽音楽?), but in the Japanese context is similar to pop music.