Koshiro's first composing job was with Nihon Falcom in 1986 at the age of 18. Falcom used compositions from the PC-8801 demo tape he had sent them in their Dragon Slayer action role-playing game Xanadu Scenario II, for its opening theme and several dungeon levels. He also wrote the opening song in Romancia that same year. His compositions for these early games were influenced by arcade game music and Japanese bands such as The Alfee. He then produced the soundtrack to Dragon Slayer IV / Legacy of the Wizard (1987), which was influenced by the sounds of early Konami games. His most well-known Falcom works are his soundtracks for Sorcerian (1987) and the early Ys games, Ys I (1987) and Ys II (1988). These early music productions mainly featured rock and fusion music. The TurboGrafx-CD versions of the first three Ys games (from 1989 to 1991) are notable for their very early use of Red Book audio in video games. Music from the Ys games were also employed in the Ys anime.
