Coincidences? Yes, we have 'em...lots and lots of 'em..... Kind of hard to recommend this one highly, if you care at all about verisimilitude.
Kiriko Yanagida, a woman in her early 20's, has good reason to detest demigod lawyer Ohtsuka, who perhaps could have saved her brother from wrongful death at the hands of the authorities in Kumamoto--but refused to even try. And then, as if by magic, the means for having revenge on Ohtsuka fall into her hands...due to not one, or even two, but at least three highly improbably occurrences.
Well, no thanks, I don't like to be asked to play dumb. If you can stomach these events, however, occurring roughly midway in the film, it is otherwise a well-wrought drama. The director Youji Yamada, near the beginning of his very, very long career, evinces bold creativity, most noticeably in the unique audio of the scene in which Kiriko has learned that Ohtsuka will not help her and that, as a consequence, her brother is likely doomed.
...in addition to this film, I have seen other films based on Matsumoto novels, and have read a few of his novels as well, and I have to say that he tends to be overrated. One Matsumoto-based film that I can recommend, however, is Suspicion (Japanese title Giwaku) (1982), which plays fair: no absurd coincidences in that one.