For the next 20 years, Kumashiro directed a string of financial and critical hits unprecedented in Japanese cinematic history, completing ten films in 1972 and 1973 alone. His prolific and successful career during these years earned him the title, "King of Nikkatsu "Roman porno"" Contrasting him with more mainstream filmmakers like Nagisa Oshima, who sometimes make use of pornographic elements in their films, "Film Quarterly"’s New York editor, William Johnson calls Kumashiro, "an indisputable maker of screen porn whose films also deserve 'serious' interest." Kumashiro's work was noted for its humanistic themes and for its sympathetic treatment of its characters. Stylistically, his films were experimental, using a variety of "avant-garde" cinematic devices, and complex narrative structure.