Did you know Jackie Chan's mother was an opium smuggler and his father was a spy? Neither did he. Geoffrey Macnab reports

How could they abandon their kids like that? It's a question that Mabel Cheung has been asked again and again since unveiling her film, Traces of the Dragon: Jackie Chan and His Lost Family. The documentary reveals some devastating family secrets that its subject, Hong Kong superstar Jackie Chan, has only recently learned himself.

When they fled mainland China for Hong Kong after the Communists came to power in 1949, Jackie's parents left their children behind. His father, whose first wife died in 1947, had two sons. His mother, whose first husband died in a Japanese bombing raid, had two daughters. For years, no one knew whether they were alive or dead.

To westerners, the idea that a parent could simply up sticks and build a new life in a faraway country without taking his or her infant children is unconscionable. To Cheung, it was a simple matter of survival.

"It was so commonplace in China. Life was cheap. It has always been cheap. It's a very common thing to do, abandon your children. In every family, there were abandoned children," she says placidly.

Her own family proves the point. She recalls a recent family funeral at which there were many unfamiliar faces - close relatives from mainland China whom she had never previously met. They too had been left behind when her grandparents made their escape to Hong Kong after the Communist takeover.

Jackie Chan is one of the best-known movie stars in the world. Given the exhaustive attention that fans pay to the private lives of their idols, it seems extraordinary that neither he nor anyone else knew the true story of his own family background.

Rumours had been swirling round Hong Kong for years that Jackie Chan wasn't his real name and that he was adopted, but no one suspected that he would turn out to have two brothers still alive and living impoverished, anonymous lives in mainland China. Nor did they have any inkling that Jackie's mother had once been a legendary gambler in the Shanghai underworld or that his father had been a Nationalist spy and gangland boss.

These are among the more startling revelations that Cheung uncovers. "The fact that his mother was an opium smuggler, a gambler and a big sister in the underworld was a big shock to Jackie and also to us," she admits. "Everybody in Hong Kong knew that his mother was like a common housewife, very kind, very gentle."

Cheung and her producer partner Alex Law (who had already made a film about Jackie's childhood in the Peking Opera Academy) were close friends of Jackie Chan. When he first approached them in the late 1990s and invited them to come with him to Australia to meet his father, they thought they were going on a jaunt that would last a few days at most.

Jackie sent the film crew ahead to familiarise themselves with the father, a still-sprightly, pipe-smoking patriarch with a passion for kung fu who is well into his 80s, but looks much younger.

"He is a very dignified kind of man," Cheung says. "He's a very forceful guy. He likes to drink whisky every day. To break the ice, we drank a glass of whisky with him for lunch and for dinner.

"After a while, we started to talk and I began to like him, because he's funny and he's straightforward and he calls a spade a spade."

Eventually, Jackie turned up - and that's when the truth-telling began. As the actor sat at his father's feet or walked with him by the sea shore, he was told the astonishing story of the brothers he didn't even know he had.

He discovered how his father first met his mother - by arresting her for smuggling opium. (With two daughters to support, she had drifted into gambling and racketeering.) And, yes, it was true that "Chan" wasn't his real name. His father, whom he knew as Chan Chi-Long, was really called Fang Daolang.

Although Fang had invited Jackie over to Australia to set the family history straight, he was still guarded and irritable when the film-makers began probing too closely into his past.

"He got very angry. He said, 'If you know everything, why didn't you ask me? You can find out from somebody else.' Jackie had to intercede. He said, 'I invited these guys to come. You've got to talk more.' We had to befriend him, sing karaokes with him, dance a little bit, before he was willing to talk again. And of course he was reluctant to tell us about his wife as an opium smuggler."

Cheung was not at all sure what Jackie expected of the film. At first, she had little idea of what to do with the footage. An acclaimed feature film director in Hong Kong, she had never made a documentary before. It struck her, though, that this was an emblematic tale. "Every single Chinese family has a story more or less like this," she observes.

Her film begins conventionally enough, with a montage of some of Jackie's best-known movie stunts in films like Police Story and Project A, but then veers off in a different direction altogether. As she tells the story of Jackie's family, she intercuts the interviews with archive material showing the sheer suffering, horror and upheaval of so much of 20th-century life in China.

There is footage of massacres and of seemingly random executions in the street; of the first world war, of the Japanese invasion, of the civil war, of citizens being humiliated - as Jackie's brothers were - during the cultural revolution.

What struck the director as she studied all this archive footage was how impassive the Chinese seemed to be in the face of their own misfortunes.

"You see all these people and when they face death, they have no expression. Maybe the Chinese are so used to suffering, they face it with almost calmness, no expression, no hysterical crying or shouting or yelling. They go to face death with a sense of calm," she muses.

Jackie Chan - who had commissioned the film - agreed to pay for the rights to all the archive footage, but he wasn't keen to try to make money out of a film that revealed such an intimate part of his life. He cried several times when watching the rough cut, but has not yet sat through the completed film.

Cheung suspects that it is too painful for him. It contains some of the last footage of his mother, who died in 2001. "He was visualising for the first time how it must have been for his parents to survive during the wars. When you're listening to the story, you don't visualise that much, but when you see the actual footage, he actually got very emotional. Maybe that's one of the reasons why he doesn't want to see it again."

In one of the most moving sequences, we see Fang returning to mainland China for a reunion with his two sons, Shide and Shishen, in a small town in Anhui province in the late 1990s. (One claims to recognise him because of the hat that he wears. The other is not so sure.) Despite his long absence, Fang quickly re-establishes his authority over the family. He buys them new suits, gets them all to pose for a group photo, and fills in the missing gaps in the family register. There's no sign of Jackie, though.

Fang has decreed that he doesn't want him to meet his two half-brothers. Nor do the neighbours realise that Shide and Shishen are so closely related to the famous movie star. If they did, the director speculates, it would cause huge upheaval in their lives.

At first, Cheung could see little resemblance between the two abandoned siblings and their illustrious half-brother. Both Shide and Shishen have dark complexions, are very skinny and have hollow eyes.

"I think it's the look of suffering: of working hard in the fields and of not having enough food," she says of their appearance. "Although now they're doing quite well, that look will stick with them for the rest of their lives. Jackie's a happy-go-lucky kind of guy, almost childlike, very warm, but his brothers are very conscious of what they say, especially to strangers like us. Jackie is in a position where he can say anything. He has power, he has money, he is rich, he is famous and he's very easy, but the brothers are very careful."

Thus far, Jackie has expressed little interest in meeting Shide and Shishen. As he says in the documentary, he feels far closer to fellow actors Sammo Hung and Yuen Biao, with whom he grew up. Besides, he's not the type to go against the will of his father. In Hong Kong, Jackie may be nicknamed "Big Brother," but in the presence of Fang, it's a different story: he is meek and respectful.

"It's a very Chinese thing that a son is always very submissive," Cheung observes. "His father pretends he's a little scared of Jackie because Jackie us such a big star, but if he's angry or he wants something, Jackie always satisfies him, always gives him what he wants."

No one quite knows what will become of Traces of the Dragon. Cheung frets that Hong Kong audiences aren't much interested in documentaries. She says that Jackie Chan is reluctant to allow the film to be shown in the US. There's little chance of it being granted a permit to be screened in mainland China unless she cuts out the archive material which forms the film's backbone.

Traces of the Dragon is thus likely to end up on the film festival circuit. It's a film, though, that ought to appeal to anyone with the slightest curiosity about the "land of the dragon" in the 20th century. As Cheung keeps on repeating: "It's not just Jackie's story but the story of every Chinese family."