In fourteenth century Japan, in the middle of nowhere, a woman and her daughter-in-law make their living by murdering and looting passersby, and dumping the bodies into a deep pit. When a friend of the dead son/husband moves back into the area and begins a sexual relationship with the daughter, the mother hatches a nefarious scheme to drive him away.
Building to a tense and creepy final act, Onibaba starts slowly and seems more of an offbeat drama for much of its running time before gradually revealing itself as a horror movie. Certainly not for all tastes, it's a stark and strange film that requires patience as it works itself towards an appropriately dark climax. Initially, I wondered if there weren't shades of misogyny in the story, what with the plot concerning murderous women who dump male corpses into a large vaginal symbol. But, if anything, the film is misanthropic; there are no positive characters, male or female, and its more about what desperate people will do to satisfy their most base needs.
The high point of the film may be a sequence in which the mother has a tense standoff with a wandering samurai, who wears a bizarre (and creepy as hell) demon mask. The mask itself was supposedly an influence on the subliminal demon faces in The Exorcist, and is a wonderfully iconic image that deserves its place in horror movie history.
Grade: B +