Hatsukoi Cider / DEEP MIND (初恋サイダー/DEEP MIND; First Love Cider / DEEP MIND) is the 13th single released by Buono!. This is the first Double A-side released by Buono!. "DEEP MIND" is used as the theme song for Gomennasai, a movie which Buono! stars in. "Hatsukoi Cider" is the ending theme to the drama Suugaku♥Joshi Gakuen. There are two editions available: Regular and Limited. This is Buono!'s third single under the zetima label.