NAMCO x CAPCOM
He also composed the soundtrack for Sega's "Shenmue" (1999) alongside Takenobu Mitsuyoshi and a few others, with Koshiro contributing fifteen original compositions to the soundtrack. Three other staff members of Ancient also worked on "Shenmue". He later composed the soundtracks for the "Wangan Midnight" series (2001 onwards) and "Namco × Capcom" (2005). These were the first projects where he wrote the lyrics along with the music. For the "Wangan Midnight" series in particular, his compositions were mostly trance music, a style he was previously unfamiliar with.