It's best to think of this movie as part of a double-feature with 'Eyes of the Spider'. They share a leading man, a release year and a theme: revenge. Sho does not appear to be a man interested in revenge. He's a math professor. But he becomes entangled and his motives only become clear later on.
9 - Already an extremely impressive film if you DON'T take into account the fact that Kurosawa produced it (plus another film) in two weeks, on a tiny budget. Less elliptical than "Cure", but equally as affecting, this surreal, coarse but never clunky crime tale acts as an astonishing essay on the susceptibility of the human mind to the urge to perpetuate cycles of violence, how they propagate, and how it must end.
Pretty devastating. Like a nightmare brought to life, progressing further and further into abstracted space, and characters being put down like animals---death as a means of becoming a corpse and nothing more. Evil's beyond our comprehension, even when we're part of it.