Well, here's a surprise. Following up on the Chez Buce readaloud of Dostoevsky's Idiot, Mrs. Buce turned up a film version from a surprising source: Japan, specifically in the work of the great (or formerly great) Akira Kurosawa.
Surprising to me, at least, and I suspect I am not alone. It's early Kurosawa and doesn't seem to me much like the films you associate with K--Rashamon, Ran, Seven Samurai. The difference goes right down to the root of style: K's Idiot is a straightforward, leisurely and linear piece of storytelling, a lot more like Ozu than the K we know (helped mightily along by the presence of Setsuko Hara, who worked so often with Ozu, in the lead role).
For my money, I'd say that K accomplishes something here that seems to elude so many directors: he takes a "classic," and instead of turning it into a mere visual aid, he refashions it into a film which--without in any way betraying the substance of the original--winds up more forceful and convincing than its source.
Well yes, the source, the source. No doubt about it, D's Idiot is an extraordinary work, fully worthy to be discussed in the same breath as Karamazov or Crime and Punishment. But it's a mess: it begins with some of the best writing D ever brought off, but then it descends into the mere shambolic as D tries desperately to figure out just what sort of project he has in mind. Surprisingly, it ends well (many, perhaps most, good novels end worse)--ends well enough to make you forget and forgive the uncertainties and blind alleys of the middle.
K pares it all down. He tightens up the plot, jettisons much of the uncertain middle, and refashions it all into a single convincing story line. He's aided by a superb cast (Setsuko Hara not least among them). It's long; it takes patience (though apparently it is not nearly as long as K wanted--go here). And there is this caveat: I'm really not sure how well it would work with a reader who hadn't already tangled with D's original. Probably here as with so many films made out of good novels, part of what the viewer brings to it is the stuff in mind from having read the book. That's undoubtedly true here also, sauced with the consideration that D has refashioned it into a structure rather more sturdy than its original.