Liz and the Blue Bird is a 2018 Japanese animated drama film directed by Naoko Yamada and written by Reiko Yoshida, based on the Sound! Euphonium novel series written by Ayano Takeda and its eponymous anime television series adaptation by Yamada and Tatsuya Ishihara. Inspired in particular by the 2017 Sound! Euphonium novel Hibike! Yūfoniamu Kitauji Kōkō Suisōgaku-bu, Haran no Dainigakushō Kōhen, the film is a spin-off sequel to the television series, focusing on the friendship of Mizore Yoroizuka and Nozomi Kasaki, two supporting characters introduced during the series' second novel. It is intended as a standalone work that can be fully understood without prior knowledge of the series.

Sound! Euphonium is a Japanese novel series written by Ayano Takeda. The story is set in Uji, Kyoto and focuses on the Kitauji High School Music Club, whose concert band is steadily improving thanks to the newly appointed adviser's strict instruction.