Rope Hell 縄地獄
Ohara Kōyū's 1978 Nikkatsu Roman Porno film starring Tani Naomi, adapted from Dan Oniroku's novel Yakuza Tenshi.
Rope Hell (Nawa jigoku) is a Nikkatsu Roman Porno feature that Ohara Kōyū made in 1978 with Tani Naomi in the lead; English Wikipedia describes Tani as best known for the studio’s SM films of the 1970s. According to the same encyclopedia, Konno Kyōhei adapted the script from Dan Oniroku’s novel Yakuza Tenshi (“Yakuza Angel”), the film runs 69 minutes and it opened in Japanese cinemas on June 24, 1978.
Its heroine, Akiko, stands to inherit a yakuza clan. A newly formed rival gang has her kidnapped, planning to hold her and so seize her family’s turf, but in captivity she comes to welcome what is done to her and turns her back on the underworld she was born into. Wikipedia notes that, like much of Dan’s work, the story turns on a character transformed through SM.
Ohara had already directed Tani in two films based on Dan’s writing in 1977, Fascination: Portrait of a Lady and Fairy in a Cage. Critics cited by Wikipedia, AllMovie and Thomas and Yuko Mihara Weisser in their Japanese Cinema Encyclopedia: The Sex Films, rated Rope Hell below those collaborations, although the Weissers praised Ohara’s visuals. The film came out on VHS in Japan in 1998.