For all its stretching of audience credibility, Nagisa Oshima's controversial 1976 film Ai No Corrida aka In The Realm of The Senses has its roots in a true-life incident from 1930's Japan, where a woman Sada Abe was found wandering about with the severed genitals of her lover Kichiza Ishida, who had been fatally asphyxiated, her name carved into his arm and the bedsheets smeared with a bloody message "Sada and Kichi, now together". Oshima takes the framework of that bizarre incident and casts Sada and Kichiza as the lead characters in this tale of sexual obsession.

Sada, who has been a prostitute at some earlier point in her life, takes up employment as a help in the inn run by Kichiza and his wife. Kichiza is almost immediately attracted to her, as she to him, and they begin an intimate liaison. It soon reaches a point where Kichiza moves her to another house and they have a mock marriage ceremony. This marks the commencement of a life dedicated to the exchange of sexual pleasures. Seemingly free of any worries of unwanted pregnancy or venereal infection, the couple seem to spend all their waking hours having sex. Sada, who resumes her occupation as sex worker to support them, forbids Kichiza from ever going back to his wife or having sexual intercourse with her, although she doesn't seem to mind if he calls geishas over, and in some instances, insists that he have sex with other women, including a 68-year old geisha. The general inference seems to be that if he has sex with another woman it should be with someone with whom he has no emotional connection with or sexual desire for. 

In time, Sada grows increasingly obsessed with Kichi-san's sexual apparatus, even threatening to cut it off so it will always remain with her. Her desperation to always be with him and ensure his sexual fidelity puts him under virtual house arrest and their carnal fetish grows more extreme with the inclusion of strangulation. The eventual climax (pun unintended) of this volatile communion mixes desire, pain, love and death in an inseparable splatter.