The Japanese film genre, which emerged in the 1960s, is commonly described as a mixture of erotic and art film. Numerous productions are characterized by their artistic ambition and their treatment of socially critical themes. Classic genre characteristics are a contractually stipulated minimum quota of sex scenes, a running time of about one hour, the use of 16mm or 35mm film and a limited budget. Japanese censorship, which forbids the showing of genitals, for example, forced directors to find creative approaches to portrayal.