Born 1938 in Osaka, Koh Hiroh was part of the Nihon University Film Study Club collective that produced Conversation between Nail and Sock (Kugi to Kutsushita no Taiwa) in 1958. His first major directorial role after graduating from university was as assistant director to Matsumoto Toshio on The Weavers of Nishijin (1961). Koh went on to direct avant-garde films and TV documentaries, and in 1980 started producing news programs and economy-themed specials for TV stations. In 2004, he worked with the city of Osaka to establish the CO2 Film Exhibition, a film festival aimed at cultivating new directorial talent. His best-known works include Osaka, Summer 1968: Anti-War Shapes (1968 Osaka no Natsu: Hansen no Bo, 1968), The Whiplashed (Muchi Utareru Mono, 1969), Ahosen—The Sakashima Pilgrimage (Ahosen—Sakashima no Junrei, 1984), and The Voice of Silence (Chinmoku no Koe, 2017).