Butter-Fly holds a unique place in Japanese pop culture as the immortal opening theme of Digimon Adventure (デジモンアドベンチャー), the 1999 anime series that introduced a generation to digital monsters. Composed and written by Hidenori Chiwata and performed by Kouji Wada as his debut single on April 23, 1999, the song captures the restless, hopeful energy of youth, its lyrics of becoming a "gokigen na chou" (a cheerful butterfly) riding a shimmering wind have become inseparable from the franchise's identity in Japan and abroad. In the maimai series, Butter-Fly debuted on July 11, 2013, as part of the launch lineup of maimai GreeN (the second major arcade version). The recording is credited to 和田光司［cover］, using Wada's own original vocal performance. The song remained playable for nearly three years before being removed from the game on June 30, 2016, less than three months after Wada passed away on April 3, 2016, at age 42 after a prolonged battle with cancer. His live performance of Butter-Fly at Animelo Summer Live 2014 in Saitama Super Arena stands as one of the most emotional public renditions of the song. The maimai chart lineup offers two designs of note. The Expert chart (Level 9) was laid out by ニャイン (Nyain), a long-serving maimai notes designer. The Master chart (Level 10) carries the designer credit 合作だよ, literally "it's a collaboration", and features 367 total notes with a notable 73 Slide notes, an unusually high count for a Standard (pre-DX) chart of the GreeN era. The song originally sat under the アニメ (Anime) genre in the cabinet; starting with maimai PiNK, it was reclassified to POPS＆アニメ (Pops & Anime), the genre label it kept for the remainder of its availability.