Riyu Kosaka (?? ????? ???, Kosaka Riyu?) is a J-pop singer, as well as a member of the Konami-produced J-Pop group BeForU. Kosaka was born in Yokohama, Kanagawa, Japan on January 17, 1985. On November 20th, 2000, Konami and Toshiba-EMI staff held auditions to form a J-pop group, which would eventually become BeForU. A good many people auditioned, and Kosaka, who was then fifteen years old, was one of four who went on to join the group. [2][3] The group, produced by Naoki Maeda, originally made songs specifically for Bemani games -- their first song, DIVE, was promoted intensely in the time leading up to the release of Dance Dance Revolution 5thMIX.