Whilst there are a few movies dealing with the theme of BDSM and the master/slave relationship, Be My Slave is absolutely the most affecting. Although it's fairly explicit in its depictions, it doesn't ever feel exploitative. The story carries emotion and weight, which sets it apart from low-level softcore movies. Kana is often put in humiliating positions at the mercy of her master(s), and Mitsu Dan, as the actress in question, is quite amazing in her vulnerable portrayal.
A note about the recent "uncut" release: The movie is very much uncut. However, as per Japanese law, there are black bars to cover a few explicit gyno shots (for example, during the shaving scene). This in no way detracts from this excellent movie.