Nagi Yanagi
From August 2009 when Supercell released their debut single "Kimi no Shiranai Monogatari", it took Ryo about a month to compose a demo of "Sayonara Memories". Continuing from "Kimi no Shiranai Monogatari", Supercell again employed the vocalist Nagi Yanagi to sing "Sayonara Memories", though officially Yanagi is not a member of Supercell. After becoming a fan of the music composed by Ryo of Supercell, Yanagi contacted him and the two talked about someday collaborating. After being offered to be the singer for "Kimi no Shiranai Monogatari", it was decided that Yanagi would be the singer for Supercell's second album "Today Is A Beautiful Day" (2011). Previously, Ryo had used the Vocaloid singing synthesizer Hatsune Miku as the vocalist of Supercell's debut album "Supercell" (2009). In switching to a human singer, Ryo said "that although he loses absolute control over the tone of each and every phrase, working with a singer adds a human element that resonates better with listeners."