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. All of these early soundtracks were produced using the FM synthesis sound chip of the PC-8801. Despite later advances in audio technology, Koshiro would continue to use older PC-8801 hardware to produce many of his later video game soundtracks, including the Streets of Rage and Etrian Odyssey soundtracks.<ref name="hg101_retro"> Reprinted from {{citation|title=Retro Gamer|issue=67|year=2009}}</ref> His soundtracks for early Nihon Falcom games, such as the Dragon Slayer and Ys series, are widely regarded as some of the most influential role-playing video game scores. Early freelance work (1988–1990) Following his separation with Falcom, Koshiro became a freelancer, composing music for many other companies. His early freelance projects included the Sharp X68000 port of Bosconian, Bothtec's action role-playing game The Scheme (1988) for the PC-8801, and Enix's visual novel adventure game Misty Blue for the PC-9801 in 1990. The latter two soundtracks featured early Eurobeat music. His most notable freelance work was for Sega, where he composed music for the Shinobi series and the Streets of Rage series, as well as Quintet, where he composed the soundtracks to ActRaiser (1990) and ActRaiser 2 (1993). His first freelance work for Sega was the soundtrack to The Revenge of Shinobi (1989), for which he produced house and "progressive, catchy, techno-style compositions" that fused electronic dance music with traditional Japanese music. His soundtrack for ActRaiser (1990), on the other hand, was mainly classical and orchestral. While working on ActRaiser, in order to get around the SNES's 64 KB memory limitation which limited the number of instruments that can be used and prevented the reloading of samples, Koshiro developed a sample loading system that worked with the ROM cartridge memory, swapping samples from the ROM data on the fly. This allowed him to "load parts of the music gradually as needed, and also change it quickly between stages or parts of a stage"