Although it is futarimai (dance in pairs) in Koma-ichikotsucho (one of Japanese chromatic scale based on Em) that belongs in uho (the right side), also known as Komagaku music, the piece is called 'Rakuson' when performed as hitorimai (solo dance).
右方（高麗楽）に属する高麗壱越調（こまいちこつちょう）の二人舞だが、一人舞の場合は曲名を「落蹲」と言う。