half an hour in and I just don't know whether to bother going on
If this were not a Kurosawa movie, and it did not have a bunch of rave reviews, I would have no difficulty giving up on this movie right now. It's really dull, with bland characters whose motivations I don't entirely understand (which can happen with Japanese films; I simply don't understand the culture well enough to understand some things that are givens in Japan). There are some clever things (the shoe-through-the-seasons bit), but also some dull ones (the endless opening judo scene). And I have zero interest in what's going on.
But maybe it gets better? It's Kurosawa; it must have some worthwhile stuff in it. And according to wikipedia it's an influential movie that has been remade countless times (suggesting that sooner or later something interesting must happen in it.
On the other hand, even later in his career Kurosawa did manage to make a few duds, so this may well be one of them.
Do the people who love this movie love it from the beginning? Because if so I might as well give up now.