The roaring popular success of Peter Chan's Wu xia in China-- renamed Dragon for export-- is no mystery: It's an adept genre exercise with rare primal depths. Liu Jin-xi (Donnie Yen), a paper-mill worker and by all accounts a meek family man, blunderingly dispatches two bandits who attempt a robbery in his sleepy Yunnan Province village, and so becomes the center of an investigation by the paranoiac detective charged with covering the inquest, Xu Bai-ju (Takeshi Kaneshiro). Xu, using circa-1917 forensics that draw heavily on his knowledge of acupuncture, begins to suspect that Liu is someone other than who he says, his "accidental" valor in fact being the work of a trained killer. The script, by Aubrey Lam, bears a marked resemblance to David Cronenberg's A History of Violence and a score of old westerns beside-- the retired bad man rustled out of retirement by figures from the past-- while the fleet spirit of the film evokes happier days of Hong Kong cinema. Although Yen does not catch every facet of his character's ambivalence, he choreographs himself flexibly shot, lucid fight duets with Kara Hui and Jimmy Wang, whose considerable bulk proves impervious to blade strikes-- Wang's 1967 wuxia The One-Armed Swordsman is, for reasons which become apparent after a rather gruesome plot twist, another partial inspiration. Dragon itself has been dismembered, shorn of nearly 20 minutes for its U.S. release, but what remains is more than sufficient to do the job.