A story about memories left in the heart.

—Jin's Song Introduction

Ayano no Koufuku Riron
Kanji アヤノの幸福理論
Rōmaji Ayano no Kōfuku Riron
English Ayano's Theory of Happiness
Song Information
Music and lyrics Shizen no Teki-P
Illustrations and Movie Shidu
Characters Ayano Tateyama
Tsubomi Kido
Shuuya Kano
Seto Kousuke
Takane Enomoto
Haruka Kokonose
Shintaro Kisaragi
Kenjirou Tateyama
Ayaka Tateyama
Sung by IA
Uploaded April 22, 2013
NND Link NND Broadcast
YT Link YT Broadcast
Album Mekakucity Records

Ayano's Theory of Happiness (アヤノの幸福理論 Ayano no Kōfuku Riron) is 11th song of the series.


This song tells the story of Ayano's past. It starts off when Kido, Seto, and Kano are introduced to Ayano by her mother. They believe that they are monsters due to their red eyes, but Ayano cheers them up by saying that red is the color of heroes. Following, she shows them a picture book of a hero story while wearing a red scarf.
Soon Ayano's mother dies due to an accident. Ayano tells herself that she has to be a good big sister and cheer her siblings up. One day she sees her dad planning an experiment on her friends, Takane and Haruka. Devastated by this, she tries to save them by committing suicide, thus entering the Heat Haze.


  • Lyricist/Composer/Guitar: Jin
  • Arranged: Ryosuke Nakanishi
  • Movie Director: Jin

Lyrics & Translation


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