Shugo Chara!
Guardians 4 released their second single, "School Days", as the second opening theme song of "Shugo Chara!! Doki" on September 2, 2009. The single contained a cover version of the song by Shugo Chara Egg! and "Itsuka Koko de" as B-side songs. The video single was released on September 16, 2009. After the song was featured for two months, Guardians 4 released the song "Party Time" as the first opening song to "Shugo Chara!"'s third season, "Shugo Chara! Party!", which began broadcast in October 2009. "Party Time" was released on November 18, 2009, as a double A-side single with "Watashi no Tamago", the series' ending theme song, by Shugo Chara Egg! The video single was released on December 2, 2009.