By JOHN COLMEY

artin Scorcese's 1995 film Casino, a drama about mobsters and the gambling business starring Robert DeNiro and Sharon Stone, is gruesomely realistic, and maybe even true to life. But it's doubtful that the famed director was as close to his source material as the makers of the upcoming Hong Kong film also called Casino. The new movie, due out in May, is financed by none other than Macau's most famous gangster, Wan Kuok-Koi, alias Broken Tooth Koi, and based on his personal saga. Producer Henry Fong says the tale was so real that the script had to be rewritten five times to hide the truth. And when Fong and the screenwriter first sat with Wan to take down his story, the two men looked at each other and turned off the tape recorder. "There was no way," says Fong, "we were going to walk around with that tape."

Was making a movie for a mobster more nerve-wracking than being a stunt man in a Die Hard flick? Not really. Wan, who was at most of the filming in Macau and helped arrange the sets, proved to be easy going and even modest--in his own way. Says actor Michael Lam, who plays a gang lieutenant: "When Wan saw me for the first time, he said, 'Hi, nice to meet you. I only know about chopping.'" Wan intervened rarely, but once told the extras to stop fooling around with the knives during the fights and "be serious,"--several ended up in the hospital with nasty cuts. In agreeing to do the film Fong bravely demanded full control and told Wan that the movie would not, as many Hong Kong films do, "eulogize the gangster life."

TIME got an exclusive advance look at Casino. Whether it succeeds in bringing the real Broken Tooth to the screen or to rise above a dozen other Triad movies is debatable, but there are revealing glimpses of the man and a few new twists on the genre. Casino portrays the violent rise of "Giant" (Wan's on-screen persona played by Simon Yam), as narrated by a reporter whom the gangster takes into his confidence. The mayhem is all there--endless scenes of gangs charging each other with meat cleavers and baseball bats, though it is not always clear what the fighting is about. More surprising are the stabs at comic relief: when Giant gives the order: "Let the war begin," 30 thugs in his living room start yelling into their mobile phones to call up the troops but stop abruptly when Giant screams again, "Hey! Can't you see my Mom is trying to talk on the phone?" Broken Tooth's true character emerges when the mob boss arrives at the casino and a string of waiters passes the message "Giant's coming," a signal to clear the glasses and ashtrays off the baccarat table in case he loses and blows up, which he inevitably does. In the last scene, after Giant slowly drives over the leg of a woman he mistakes for an assassin, the reporter asks him if being on top is worth doing that sort of thing. "It's not whether you like it or not," answers Giant. "That's the rules of the game."

Moviegoers who have followed the Triad wars will have a good time figuring out the real models for the main characters (many of the extras are Wan's actual followers). Who, for example, is the mysterious Mr. Chan who tries and fails to stop the two mob bosses from going to battle? Tip: screen names are homophones of real names. And for those still confused, a sequel is contemplated. Maybe this time Scorcese will take a crack at it.