It's when the dancing begins that this relaxed movie starts to spark. Lau is a tremendously energetic dancer, and there's excitement in each supercharged gesture. But the most striking transformation occurs in his face -- during one of his routines, Lau produces a truly uncanny effect. He pulls in his facial muscles so that his entire face tightens and recedes from view, and the only thing we can focus on are his eyes. At this point his gaze has become so fiercely linear that it is almost a concrete thing; he turns it directly onto his partner, marking her out as prey, and cuts a line toward her across the floor. Lau's sexual presence in "Dance of a Dream" -- self-conscious yet persuasive -- is extraordinary.

In addition to its U.S. release, "Infernal Affairs," one of Lau's most successful films, has been optioned by Brad Pitt's production company, with an eye to developing Lau's role for Matt Damon. Yet it's hard to imagine Hollywood being able to cope with someone like Lau, or with the kind of contradictions that thrive in the Hong Kong mainstream. Hong Kong films are odd creatures -- able to reconcile spiritual scenes with product placement (a blue Kleenex logo flashes before the tissue dance in "Running on Karma"), and often combining supernatural elements with the kind of gritty police procedural scenes that might be found in a documentary re-enactment. In Hong Kong, Lau is regarded as more than an actor -- he's a canny businessman, a facilitator. He functions as a goodwill ambassador between Hong Kong and the mainland, and he uses a similar actorly style in his televised speeches as he does in his films. He seems to enjoy his image as a cool negotiator -- friendly and "accessible," perhaps, but someone who behaves and emotes with precision.

Lau started his career in Hong Kong television in the mid 1980s. He played a series of oiled-up hunks in martial arts dramas; in fact, my first recollection of him is as the good-natured, shirtless disciple of a sort of benevolent goddess figure, who had adopted him as a child and was grooming him to become her next lover. Then, in the second phase of his career, he graduated to playing a slightly ironic hunk -- the sort of awkward looker who might be played by Henry Fonda, or Ryan O'Neal. In the screwball "Tricky Brains" (1991), he played a clunky Clark Kent figure, a little self-deprecating, but with his bone structure used as the butt of the joke.

But somewhere along the line, it seems, the hunk acquired an ego: the desire to make his shrewdness known to the world. The result has been a series of films developed by him and his frequent collaborator, director Andrew Lau (no relation), in which the actor plays an available romantic lead, but exposes his potential slyness either in the course of the plot or through his own line readings. In "Dance of a Dream," Lau has the satisfaction of awakening, then disturbing the female audience's desires. We see that this man, despite his vibrant physicality, is dangerously enclosed: the deliberately strained politeness he has when dealing with rich women, the sudden tightness of the mouth, the "discreet" smile he gives at the suggestion of being undermined. Any attraction is replaced by the erotic fear we have of this man; he completely disrupts the idealism of the women's picture.

However, the best evidence of Lau's decadence as an actor is "Infernal Affairs" -- see the way he relishes his role as a double agent, a man who insinuates intent into every scene. Lau's character, a detective on the mafia's payroll, pays courtly attention to his clothes, smoothing down a sleeve or a trouser leg as he walks; he's a more elegant cop than most, and carries himself with the proper self-regard. The film clearly enjoys photographing him in this classy context -- he's seen investigating sleek surfaces, sliding through glass panels, running down a staircase in a series of trim little steps.

But Lau obviously loves this role for the opportunity it gives him to show off his full range of effects. He plays this double agent as a man who requires a different set of gestures and expressions for every person he talks to -- his fiancé, fellow cops or his superiors. He consciously modulates the pitch and tone of his voice; he also has the ability to switch between dynamic and understated in his movements. Sometimes we hear his soft-shoed stalk across corridors; at other times, he walks in distinct, separated steps, with the odd syncopated beat thrown in for jazz. His everyday movement consists of chic, compressed gestures, which he uses to indicate, for instance, that he wants a drink. The crucial scene in "Infernal Affairs" in which he reveals his motivations to his boss sums up Lau's sensibility as an actor -- instead of looking tense or conflicted, Lau has a faint, nearly comic expression on his face, and he looks almost conspiratorial as he takes the final shot. This is an actor/character who is too sophisticated to reveal "evil" directly, but unable to disguise the pleasure of being exposed as a villain.

That this ambiguous man is at the center of one of the world's great film cultures is difficult to absorb. He's a resolutely commercial actor who delights in piercing the romantic dream; he alternates between jostling with other men and giving them an uncannily soft look. He seems to be able to indulge his own predilections for excess and theatricality onscreen, yet his image as a strict professional is undisturbed. In Hong Kong, Lau is even thought of as a conventional actor, with a proficient, unexceptional technique. Many were surprised when he recently won Best Actor at the Hong Kong Film Awards, for "Running on Karma" -- because of his mainstream success and his highly publicized singing career, Lau has never received serious critical attention.

More than any performer I can think of, Lau raises questions about how apparently "marginal" qualities can become ubiquitous in a culture. In Lau's case, I think the answer lies in the fact that we tend to focus minutely on each of his gestures; with his sharp moves and glances, he always seems to be in the eyeline, and thus any doubt or incredulity about his performance is erased. Lau's body language in "Infernal Affairs" is a riveting narrative in itself -- it's possible to lose sight of the entire plot while watching him tap a long envelope against his leg, or seeing his quick eyes work through diagrams. So his decadence is disguised as "getting into character," and the man whose acting may be the most radical in movies flies under the radar. Let's hope it stays that way.

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