This is Japan Calling: In the Realm of the Senses (1976)

If for nothing else, Nagisa Oshima's shocker proves one thing: there is a very fine line between porn and non-porn. And don't ask me what that fine line represents or how In the Realm of the Senses belongs to the latter category. It just does. Deal with it.

The film, whose based on a true story credentials are revealed by a redundant final voice-over, doesn't have a plot per se. It can be described as thus: a servant girl (formerly a "whore") falls for her virile master. They hook up. Again, and again ... and seek new realms of senses, if you please. However, while seeking for a heightened sexual ecstasy, things get a little out of control and blood begins to flow.