"Soul's Refrain" is the second major theme song for
Neon Genesis Evangelion performed by Yoko Takahashi following the television series' opening theme "
A Cruel Angel's Thesis". The song was born following discussions surrounding the creation of a theatrical film after the TV series finale. During pre-production, it was undecided whether "Soul's Refrain" or another song, "Kokoro yo Genshi ni Modore" would be used in the film. "Soul's Refrain" was composed by Toshiyuki O'mori, while "Kokoro yo Genshi ni Modore" was composed by Hidetoshi Sato, though both tracks were arranged and produced by O'mori. He approached the task professionally, stating he would produce the highest quality possible for both tracks, regardless of which one was ultimately selected. At the time of development, the movie producer Toshimichi Otsuki provided Oikawa with a videotape including only one television episode—in which
Rei Ayanami dies but then returns to life— and two demo tapes (for the tracks that would become "Soul's Refrain" and "Kokoro yo Genshi ni Modore"), as it had not yet been decided which would serve as the theme song. The instructions she received were simply to write whatever came to mind after watching the footage. The lyrics for "Soul's Refrain" were not finished until the very day of the recording session. The lyrics were sent to the recording studio via fax, after which staff wrote them by hand onto the sheet music, and Takahashi then recorded the vocals for the track. Takahashi commented: "Everyone was pushing and struggling together to make the best possible work, so during that recording—with “Kokoro yo Genshi ni Modore” also being made at the same time—I approached it even more professionally than before, determined that whichever song was chosen, it would be ready." she did not find out which song had been chosen, and in which part the song would be played, until she watched the film in the theatre. Takahashi has stated that "Soul's Refrain" was significantly easier to sing than "A Cruel Angel's Thesis", attributing this to well-placed breath points that align naturally with the song's musical dynamics and variations in strength. == Concepts and themes ==