Yuzo Koshiro (古代 祐三, Koshiro Yūzō, born December 12, 1967 in Hino, Tokyo) is a Japanese music composer and president of the game development company Ancient. He is often regarded as one of the most influential innovators in chiptune and video game music, producing music in a number of genres, including various electronic genres (such as breakbeat, electro, hardcore, house, jungle, techno, and trance), experimental, symphonic, hip hop, jazz, and synth-rock. Koshiro and his sister Ayano also founded the game development company Ancient in 1990.
Koshiro has been cited as creating some of the most memorable game music of the 1980s and 1990s, contributing for games such as Nihon Falcom's Dragon Slayer and Ys series, as well as Sega's The Revenge of Shinobi and Streets of Rage series. The Streets of Rage soundtracks are considered by some to be ahead of their time, featuring a "blend of swaggering house synths", "dirty" electro-funk, and early trance elements. His influence also extends to the popular music industry, particularly within the electronic dance music and chiptune communities.