Kurenai no Kisetsu (クレナイの季節; Crimson Season) is the 5th single by v-u-den. The first press of the single came with a photo card. The single was released on October 5, 2005. The single V was released on October 13, 2005. The single reached #14 on the Oricon charts and charted for three weeks, selling 14,192 copies. The single V reached #2 and sold 6,057 copies.