Is Lars von Trier actually Satan? Watching him in The Five Obstructions, you could be forgiven for wondering. There's that evil grin, that impish little face, the eyes that burn with something much worse than mischief. The amount of perverse joy he gets from torturing his hero, fellow Danish filmmaker Jørgen Leth, makes you grateful you're not one of his favorite directors.

For von Trier, making movies is a game, and games have rules. Self-flagellation is one of the rules. Throughout his career, from Epidemic to Dogville, he has imposed rigorous constraints on his actors and his characters, but most of all on himself. The Five Obstructions, he says, is his chance "to flagellate someone else."

And really, what artist doesn't secretly want to be tortured, just a little? Whatever doesn't kill you makes you stronger, right? Leth, a professor at the Danish Film Institute, taught many of von Trier's Dogme 95 cohorts and has had a clear influence on that minimalist movement. He turns out to be not just the perfect victim for von Trier's diabolical machinations, but also a worthy adversary.

Leth's 1967 short film The Perfect Human exemplifies his almost anthropologically cool, distant style. It's a breakup story disguised as a nature documentary, with Leth narrating as the camera detachedly observes the Perfect Man and the Perfect Woman against a stark white background, eating, dancing, sleeping. Von Trier, when he worked as an intern at the archives of the Danish Film Institute, says he watched the film something like 20 times.

Now, the student has become the teacher.

In The Five Obstructions, von Trier and Leth agree that Leth will remake The Perfect Human five times, each time with a new set of obstructions invented by von Trier. The obstructions are aimed to get at Leth's weaknesses * confessions he makes, things he fears, his inclinations as a filmmaker, his tendency to observe from a distance, his struggles with depression. It's not entertainment; it's therapy. And not just for Leth. This playful but dangerous game clearly has Oedipal overtones. Von Trier wants to see his hero crumble, he wants to break him and find out what's inside. The whole project is sadistic and affectionate in equal measure, and it's fascinating to watch.

For the first obstruction, Leth--famous for long, unedited takes--must remake The Perfect Human with no shots longer than 12 frames. He must do it in Cuba, where he's never been. And he must answer the questions he asked in the original film.

Watching the older director accept these rules is almost heartbreaking at first. His tired face sags with each new constraint. He keeps smiling, but you can tell he thinks his tormentor might've gone too far. Afterward, he growls at the camera: "It's totally destructive! He's ruining it from the start!"

Not hardly, as it turns out. Leth takes his crew to Cuba and comes back with an utterly gorgeous, slightly twitchy but poetic remake of The Perfect Human (we see most of the remakes in abbreviated form, often spliced together with the original). Von Trier is astounded. "The 12 frames were a gift!" shouts the puppetmaster, outraged but clearly impressed.

Having failed to crack his hero's facade, von Trier demands an even more brutal set of obstructions. For the second segment, Leth has to visit the most miserable place in the world, but not film it. Then he must portray his experiences there without showing them. Leth has to star as the Perfect Man himself. Von Trier is hoping to force Leth out of his habitual role as the detached observer. It doesn't work, but once again the "student" produces a beautiful, miniature masterpiece that enrages his "teacher."

"I like the idea of how Muhammad Ali beat George Foreman by lying back on the ropes and absorbing the blows," Leth said in an interview with the Guardian. It's the perfect defense for the kind of attack he's under.

The third and fourth obstructions are just as evil: In one, Leth has to make a cartoon, a format both he and von Trier despise, and in the other he's given no rules whatsoever. It's the cinematic equivalent of Celebrity Boxing. But he never cracks, and in the end the devil gets his due. By the time they arrive at the fifth obstruction, it's no longer as simple as teacher vs. student, tormentor vs. victim. Von Trier sums it up the best: "It's the attacker who really exposes himself."

The Five Obstructions

Not RatedCinema 21, 616 NW 21st Ave., 223-4515. 7 pm Friday-Thursday, Aug. 27-Sept. 2. Additional shows 2:30 pm Saturday-Sunday. $4-$7.