An intro to K-ON!
In K-On!, four Japanese high school girls join the light music club of Sakuragoaka Girl's High School to try to save it from being disbanded. However, they are the only members of the club. At first, Yui Hirasawa has no experience playing musical instruments or reading sheet music as she is only familiar with playing the castanets, but she eventually becomes an excellent guitar player. From then on, Yui, along with bassist Mio Akiyama, drummer Ritsu Tainaka, and keyboardist Tsumugi Kotobuki spend their school days practicing, performing, and hanging out together. The club is overseen by music teacher Sawako Yamanaka, who eventually becomes their homeroom teacher as well during their final year of high school. In their second year, the club welcomes another guitarist, underclassman Azusa Nakano. After Azusa joins they gain more structure and begin to practice more.
After their third year, Yui, Ritsu, Mio and Tsumugi graduate and enroll into a university. There they join its light music club alongside three other students: Akira Wada, Ayame Yoshida, and Sachi Hayashi. Meanwhile, Azusa continues to run the high school light music club alongside Yui's sister Ui, their classmate Jun Suzuki, and new members Sumire Saitō and Nao Okuda.
A 13-episode anime adaptation produced by Kyoto Animation aired in Japan between April and June 2009. An additional original video animation (OVA) episode was released in January 2010. A 26-episode second season, titled K-On!! (with two exclamation marks), aired in Japan between April and September 2010, with an OVA episode released in March 2011. An animated film based on the series was released in Japan on December 3, 2011. Bandai Entertainment had licensed the first season until their closure in 2012. Sentai Filmworks has since re-licensed the first season, in addition to acquiring the rights for the second season and film. The title of the series comes from the Japanese word for light music, keiongaku (軽音楽), which in the Japanese context is similar to pop music.
Two pieces of theme music are used for the first season; one opening theme and one ending theme. The opening theme is "Cagayake! Girls" by Aki Toyosaki with Yōko Hikasa, Satomi Satō and Minako Kotobuki. The ending theme is "Don't say 'lazy'" by Hikasa with Toyosaki, Satō and Kotobuki. From episode nine, the opening video features Azusa, and also features some minor changes to the music, particularly an additional guitar part during certain segments (alongside the initial two). Four pieces of theme music are used for the second season; two opening themes and two ending themes. For the first 13 episodes, the opening theme is "Go! Go! Maniac" and the ending theme is "Listen!!". For episodes 14 onwards, the opening theme is "Utauyo!! Miracle" while the ending theme is "No, Thank You!". The songs from the second season are performed by Toyosaki, Hikasa, Satō, Kotobuki, and Ayana Taketatsu, with Toyasaki and Hikasa singing lead vocals on the opening and ending themes, respectively.