Let's address the elephant in the room. Watching Hadaka no Tenshi 1981 on Ok.ru is technically piracy. The rights to the film likely belong to Nikkatsu Corporation (or a successor company like J-BOX).
While not strictly a "Roman Porno" (a brand-specific genre by studio Nikkatsu), Hadaka no Tenshi shares DNA with that style. These films were produced on low budgets but with high artistic ambition. Directors were given creative freedom as long as they delivered the requisite amount of nudity. This paradox resulted in some of the most interesting genre films of the era, where high-art composition existed alongside exploitation tropes. hadaka no tenshi 1981 ok.ru
Would a more detailed summary of the production staff or a list of other works by the lead cast be helpful? Hadaka no tenshi (1981) - IMDb Let's address the elephant in the room