Watching Lee-Chang Dong's Poetry, I was reminded quite irresistibly of Bong Joon-Ho's Mother, and not only - at least I hope not - because both are South Korean films about matriarchs forced into terrible ethical decisions to safeguard the future of their young male heir. Though God knows, films have been compared on weaker grounds.

Both films are also genre experiments, after their fashion, even the same genre experiment: there's a bit of nasty-minded sexploitation thriller over here, and a huge scoop of '50s-style women's picture right there, but the tone is never as melodramatic as a plot summary would make it think. There's a theme of feminine identity in the face of a reflexively masculine culture that is presented so deftly and subtly that you could be well forgiven for entirely failing to notice that it's there at all. And the thing that lingers most after you leave the film behind is the performance of its lead actress, a difficult piece of work that unites several disparate impulses and emotions into one remarkably coherent whole, and in so doing gives the film entire a stability it would otherwise lack.

None of this is meant to make any kind of blanket statement about South Korean filmmaking, or anything; just to acknowledge that for all its strengths, Poetry has one heck of a ghost hovering over it. Mother was, after all, one of the best U.S. releases of 2010, and not the sort of thing that just any old film could unblinkingly compete with. It's a sign of Lee's estimable skills as a filmmaker, in fact, that Poetry ultimately emerges as its own thing to the degree that it does, a mini-masterpiece that's a bit flawed and all - it's in desperate need of a nip and tuck here and there, and some of the metaphors are overblown - but absolutely captivating, even as it is stately and slow and features many passages in which, if we are being wholly honest, nothing as such "happens".

In the beginning, there is a river, and in the river, there is the body of a young girl. We'll learn soon enough that she committed suicide, and then a little bit later we learn why; but first we meet our protagonist, Mija (Yun Jeong-Hie), sitting in a hospital waiting room, watching a news report of a parent mourning the loss of their child in a war zone.* On the way out of the hospital, Mjia passes by the dead girl's body on a stretcher, and observes her tearful father, echoing the news report, obviously enough: and that brings up one of the most distinctive traits of the movie, the immaculate, subtle way in which ideas, words, and images are brought up again and again throughout. It's a poetic device that's being used, in essence, and it makes sense that a movie called Poetry would structure itself as a poem rather than a narrative film; though not knowing Korean poetry even a little bit I probably oughtn't pursue that line of reasoning very far. Still, the way that scenes repeat and reiterate one another, and inform one another through the repetition - the way that the film replays itself over and over with small variations - is self-consciously (and certainly not unsuccessfully) literary, and it creates a most electrifying mood, stimulating even though it really does seem like it ought to be sedative.

Pushing on: Mija's grandson Jong-Wook (Lee Da-Wit) is a tedious little shit in the manner of teenagers (his parents are divorced; his mother is out of the country on what seem to be general "extended mental vacation" grounds, and his father has just plain dropped out of the picture), and Mija puts up with quite a lot that she certainly doesn't need to. Even her addled grandmotherly love is put to the test when the fathers of his five closest friends pull Mija into their circle of confidence, letting her know that the six boys were responsible for raping the dead girl systematically over a series of months, and that's what drove her to commit suicide. By the time Mija learns of this, there's already a plan in place to buy the girls' parents off, with the full endorsement of the school; it's going to require her to spend a sum of money she can't even fathom acquiring, and she also seems a little bit blinkered by the blandness with which the fathers all simply accept that this will give the boys a clean slate.

This all comes in the midst of a bit of a medical crisis: remember that trip to the hospital Mija made at the beginning? She has the first stirrings of dementia, it turns out, and things are only going to get worse; perhaps in response, and perhaps in a moment of pure serendipity, Mija is also taking adult classes in poetry writing, and has started going to the local poetry appreciation society.

The three threads of the film don't tie in together as cleanly as they might - the dementia plotline in particular wanders out of view altogether for long stretches of the film - yet it's hard to say that the film would really be more satisfying if it were tighter. In fact, the shagginess is part of what gives Poetry its effect: that willingness to settle on scenes that spin around a bit, and the lack of anxiety about linking things in any deterministic way gives it most of its brightly meditative feel, as the film aligns itself with Mija's now-desperate, now-reflective attempts to perceive and describe beauty around her. The film gets to jump ahead of her there: while she struggles with words, Lee and cinematographer Kim Hyun-Seok get to show what she cannot tell, creating her poetry for her, in effect, and at the same time putting us somewhat in the same position as the character, taunting us to put into words the same images that she fights with.

And so it is, that many of the best moments in the film are a sort of mixed-up impressionist existentialism, which is a tremendously useless description; but I can't think of a better way to describe sublime moments such as Mija's confrontation with the dead girl's mother, the climax of both major subplots in the movie (Mija's inability to find words, her confusion and disgust at being thrust into a crudely misogynistic and materialistic attempt to wish away the horrible death of an innocent young woman), one that is beautiful and warm on the one hand, vaguely terrifying on the other.

Primarily, the film is attempting to make us understand Mija's inner life even as that inner life is disintegrating, a daunting task that Yun executes with admirable grace: coming out of a 16-year-retirement to play in this movie, and having done the bulk of her work in an era of Korean cinema that most Western audiences have never been able to see, the actress feels both like an exciting discovery and a canny old veteran who knows every trick in the book , and her performance, commandingly uniting the first tendrils of dementia with the rising frustration of the blocked artist, the fear of an old woman on the verge of losing her only loved one, and the barely-formed suspicion of knowing that what she and her co-conspirators are about is just wrong, is absolutely revelatory; even when the film around her doesn't quite gel, Mija is a profound characterisation. She is not able to express herself to the world, but she more than successfully expresses herself to us, and the movie constructed around her is a lumpy, yearning triumph: cutting in its depiction of social barbarity, beautiful in its depiction of everyday moments. There are moments as simple as a street game of badminton that strike with all the expressive force cinema can muster. And there are plots and characters and scenes that don't work - the lady poet that Mija befriends who has no consistent personality of her own, the use of Western animated characters as a motif in the early part of the film, the uncertain depiction of the news media - but a polished Poetry could never be as heartfelt and moving as a scruffy, imbalanced Poetry. Imperfection, here, is perfection.

*Idiotically, I didn't make any note at all of the details, though I think it was one of the American-led wars.