ゆりゆららららゆるゆり大事件 (Yuriyurararara YuruYuri Daijiken) is the opening theme song for the first season of the YuruYuri (ゆるゆり) anime series, performed by 七森中☆ごらく部 (Nanamorichu☆gorakubu), the voice-actress unit comprising the four main cast members. The track was composed by Ken Iijima, arranged jointly by Iijima and Pierre, with lyrics by Miya, and originally released as a single in 2011. Its title is a playful, tongue-twisting string of similar-sounding syllables that evokes the show's comedic, slice-of-life tone. In the maimai rhythm game series, the song was added at the launch of maimai MURASAKi on December 15, 2016, appearing under the POPS & ANIME category. The in-game background video directly uses the YuruYuri opening animation, preserving the original visual context. The track was removed from the game on July 11, 2019, and was exclusive to the Japanese version of maimai throughout its lifespan, making it a legacy song inaccessible in current standard rotation. The Master chart, designed by rioN at level 10+ (constant 10.6), stands out for its 470-note composition with 93 Slide notes, an unusually high slide density relative to its total note count for a mid-2010s maimai chart, reflecting the song's bouncy, free-spirited energy.