The choir is Sopra il fiume (nickname: Sopra), a youth mixed voice choir from Saitama Prefecture.
In Saitama Prefecture, where choral music is popular among men and women of all ages, it was founded in June 2018 with the aim of becoming a group where choral lovers of the youth generation, regardless of their background, can engage in ambitious activities. The name of the choir, which is in Italian, represents the city of Kawagoe in Saitama Prefecture, where they are based.
Without inviting a permanent teacher, the choir aims to actively pursue the possibilities of choral music and to enjoy music with only its members.