Released simultaneously with the clear sky blue vinyl edition of "ISSHOKU SOKUHATSU" is the first-ever reissue of the single "Sora Tobu Enban ni Ototo ga Notta yo" on 7-inch. Originally released after the band made their major debut with their first album "ISSHOKU SOKUHATSU" on Toho Records in 1974, this single came out during a transitional period when the lineup expanded to five members.