Hana to hebi: hakui nawa dorei AKA Flower and Snake 4 - White Uniform Rope Slave (1986) - Shogoro Nishimura

Quote:
This film is originally from the famous erotica author Dan Oniroku's novel Flower And Snake series. Dentist Oba is handsome and successful, but he remained single over the years. Oba is treating his nurse, Naoe, as his sex slave. He also satisfies himself sexually when he anesthetizes his female patients. When he meets Miki, he can't help but turn her into another sex slave. Miki and her Master, Mrs. Ito, are lesbians. When Miki is kidnapped by Oba, Mrs. Ito is also imprisoned by Oba…
– DVD cover blurb

Hana to hebi: jigoku-hen aka Flower & Snake -Sketch of Hell (1985) - Shogoro Nishimura

IMDb review:

Pause for a disco dance in the midst of all the rape and torture

This is the first of the many remakes of Masaru Konuma's 1974 classic, based in turn upon the writing of Oniroku Dan. Again a big enema scene is at the centre of this telling of the tale and whilst it is a bit wince inducing, it does not quite have the nasty edge of the original. Beautifully, colourfully and gleefully shot, this is an amazingly focused tale of capture, bondage but more especially humiliation. Much is made of the two naked female protagonists being mother and step-daughter and despite the explicit close-ups of the proceedings, there is always room to show the men and women enjoying the 'spectacle'. The serious tone is set at the start and apart from a pause for a disco dance in the midst of all the rape and torture and the eye popping and completely OTT ending, things remain on that level throughout. Amazing and it is only regrettable that the English language does not seem to have words to describe just how amazing Japanese cinema can be.

Dan Oniroku nawa to hada AKA Rope and Skin (1979) - Shogoro Nishimura

Synopsis: Okuma was a woman gambler until she retired from the yakuza world.
Two years later, she returns home, and finds that the big boss has been
assassinated and his daughter is having trouble keeping things in line
against the rival gang headed by the men who killed her father. Okoma
decides to take things into her own hands.

Dan Oniroku nawagesho aka Rope Cosmetology (1978) - Shogoro Nishimura

Description:
Nikkatsu Romano Porno starring Naomi Tani. In this one she plays a bored and sexually frustrated housewife who runs into an old friend whose husband is an artist specializing in paintings of women in bondage. The plot unfolds just as you'd imagine, only with more (simulated) dog on woman sex than usual. This is not a good movie for sensitive souls. However perverse the film is, though, its "message" is essentially conservative, as Tani and her husband gain a new appreciation of one another through candles, crucifixion, and canine play. S/M is a sort of couple's therapy, and their marriage is saved. Would Dr. Phil approve?