The band's vocalist Ozaki Sekaikan commented that when he first met the director, he was touched by how much trust he had in their music and was prepared to leave things to them in creating a suitable theme song for the film. As such, they managed to create a song which will represent their joy at being given such a chance to showcase their music. Suda who had heard the song, complimented the powerful melody and inclusive lyrics which were amplified by Ozaki's warm and sharp vocals. As such, he had a lot of respect for the band and revealed that he almost felt like crying after listening to this.
"Teiichi no Kuni" will be shown in cinemas from 29 April.