K-On! is a Japanese four-panel comic strip seinen manga written and illustrated by Kakifly. The manga is licensed in North America by Yen Press.A 13-episode anime adaptation produced by Kyoto Animation aired in Japan between April and June 2009. A 26-episode second season, titled K-On!! (with two exclamation marks), aired in Japan between April and September 2010.The title of the series comes from the Japanese word for light music, keiongaku,which in the Japanese context is similar to pop music.