The zen is mightier than the sword in Jet Li's (search) latest martial-arts flick, "Hero," opening Friday.

"Usually an action film has a formula: The good guy gets in trouble, his wife dies, his parents die, he goes to the mountain, he learns martial arts, he comes back and kills the bad guy," Li told The Post.

But Li says he's tired of seeing that movie, much less making it. So he jumped at this Zhang Yimou (search)-written and -directed script, in which an assassin confronts not only the man he has trained for 10 years to kill — but also the consequences of doing so.

"This film tells you that violence is not the only solution," says the actor, 41, who became a Buddhist (search) in 1997 — a seeming contradiction to his bloody roles.

"Before Buddha became Buddha, he also used violence to save people and kill the bad guy."

In all martial arts, Li explains, the third and highest level attainable is the desire not to use martial arts at all. (Li was the national martial-arts champion of China by age 11.)

"The first level is physical, where somebody uses the sword like your longer arm," he says. "In the second level, you don't have a sword, but your heart is the sword. You can use words and imagination to stop war.

"In the highest level, you don't have a sword and your heart doesn't have a sword.

"Without a war in your heart, what is left? Only love."

Not that "Hero" bears any resemblance to a chick flick.

Li's character, a country lawman named Nameless, takes on several opponents in that highly stylized, wall-climbing "Crouching Tiger, Hidden Dragon" (search) fashion all 12-year-old boys and Quentin Tarantino live for.

Hong Kong superstars Tony Leung Chiu Wai and Maggie Cheung — fresh from their award-winning performances in Wong Kar-wai's "In the Mood for Love" — reunite to play two of the deadliest assassins imaginable.

Loosely based on real events in China in the third century B.C., "Hero" is the story of an assassin granted an audience with the ruler of the Qin kingdom, who has murdered his parents and thousands of others in an attempt to unify all seven kingdoms into one China.

Why "Hero" took so long to reach America, when Asia screened it back in 2002 (winning an Oscar nomination for Best Foreign Film), is a mystery that may cost Miramax, the U.S. distributor, at the box office.

"I really want to know the answer also!" Li yells, laughing, "because all the people say, 'Hey! I watched "Hero" on DVD!' Everybody saw the DVD!"

The title was a hot rental in Chinatown last year, and Li says his producer estimates lost revenues in his native Hong Kong alone at $20 million.

But Miramax is now attempting to neutralize the damage: They've even tacked on to the ads for "Hero" the name of its biggest star.

"Quentin Tarantino Presents," scream the movie poster and TV ads — even though the director had nothing whatsoever to do with "Hero."

"Miramax decided that Quentin can help promote this movie," says Li. "But my philosophy is just to do my best."