Ayano no Koufuku Riron (アヤノの幸福理論)

“Ayano no Koufuku Riron” (アヤノの幸福理論) is the third opening theme for Kagerou Project (カゲロウプロジェクト), the 2014 anime series animated by Shaft. The recording is performed by Jin, a Vocaloid producer, with vocals by Aki Okui. Its role as OP 3 places it within the series’ opening-theme sequence rather than as an insert or ending song.

Jin is credited as the song’s composer and lyricist. Musically, the track combines J-Pop with rock elements characteristic of his work. “Ayano no Koufuku Riron” was included on Kagerou Daze, an album released in 2014. The title is presented in Japanese as アヤノの幸福理論, while the song’s credited performing identity is Jin featuring Aki Okui.