UNDER17

UNDER17 (アンダーセブンティーン) was a Japanese duo formed by Momoi Haruko and Koike Masaya, known for performing upbeat songs for anime and video games. Their music became especially recognizable through Momoi Haruko’s distinctive vocals and playful, catchy lyrics, which helped define the group’s appeal among fans of anime music and game themes. During their active years, UNDER17 contributed songs to several anime series, including DearS, Kujibiki Unbalance, Tenbatsu Angel Rabbie, Mouse, and Popotan. They also recorded opening songs for adult video games, further connecting their work to the wider otaku and game music scene. The duo announced their breakup on September 27, 2004, after Momoi Haruko and Koike Masaya decided to pursue separate paths because of creative differences. Although the group ended, their songs remained closely associated with the early-2000s anime and game music landscape. UNDER17 later reunited for a one-song performance at Animelo Summer Live on August 31, 2008, offering fans a brief return of one of the era’s most recognizable duo acts. Their catalog continues to be remembered for its energetic style and strong ties to anime and video game culture.