Born in Japan in 1941. Kôyama attended Nihon University but quit midway to join the independent production company Kindai Eiga Kyokai, where he worked as an assistant director under such directors as Kaneto Shindō, Kōzaburō Yoshimura, and Tadashi Imai. He made his directorial debut in 1971 with the children’s film “Koi No Iru Mura”. He also directed “Furusato” (1983), “Shiroi Te” (1990), “Gekko No Natsu” (1993), “Gujô Ikki” (2000), and “Doctor’s Wish” (2014).