This movie isn't for everyone. A number of Satõ's films aren't. For those that are, you will not want to miss seeing this one.
Not a complicated plot. A psychologist that studies people by making them listen to white noise and staring into a mirror. His wife is one of his subjects. He also subjects his wife to various S&M activities which she does not enjoy. So she leaves. Enter her twin sister that does enjoy those activities...
Those activities include: Bondage, masturbation, spanking, knife play, suspension, using an apple core as a gag, food spat into face, Kissing eyeball, rubber gloves and more. All is a part of the story. Not for the timid or squeamish. This is considered a Horror movie although it really defies any label. Except it is a pink eiga. You may or may not find the sex scenes erotic. I found it more an extension of the characters.
The cast is two people. Kiyomi Ito and Kazuhiro Sano who are both excellent. Kiyomi Ito plays both twins of course. If she didn't, she deserved an award for her performance. One of my favorite Japanese actresses. Their acting really pushed this movie to another level and made it fully work.
This is one of Director Hisayasu Satõ's best. Some people may see this just as a vehicle for the sex scenes. I say the sex scenes are a part of the story, driving it forward. I thought about rating it a 9 instead of a 10 but I couldn't think of anything to deduct. I highly recommend watching.