While proud of her accomplishments at Joss, Tang is self-deprecating about her films, saying it's fortunate that they're hard to find these days. 'Every time I make a film, I wish nobody would see it - therefore I let the copies and everything deteriorate,' she says. 'If they don't want to see it, so much the better for me.'

But critics and film buffs beg to differ. They search out the films, and with good reason. Tang was a pioneer, in terms of the issues her movies addressed and how she made them. When local movies were still drenched in unflinching machismo, she made subtle films about the sexual oppression resulting from traditional Chinese values.

Shunning simple visual thrills and conventional storylines, Tang's work was also seen as the precursor to films by new wave directors such as Ann Hui On-wah and Yim Ho. Her status as the forerunner to Hong Kong' art-house cinema movement was cemented by her use of sophisticated camera work and editing. Tang's debut, The Arch, features the cinematography of Satyajit Ray's long-time associate, Subatra Mitra, and editing by Les Blank, who would later become famous for his documentaries on German director Werner Herzog.

Tang's self-imposed exile to Los Angeles has elevated her to the status of a lost legend in local film history. She rarely returns to Hong Kong and seldom makes appearances at screenings of her own work. Even veteran film researchers have difficulty luring her out of retirement to talk about her work. All this has meant Tang's work is becoming lost to a new generation of movie-goers, who are largely unaware of her small but significant output.

The Hong Kong Film Archives' screening of China Behind on Tuesday, as part of a retrospective of landmark movies from the 1970s, should illustrate Tang's significance in the development of Hong Kong cinema. Her second feature film, China Behind was a humane and insightful look into the Cultural Revolution. The story revolves around five mainland intellectuals who escaped the madness by swimming to Hong Kong. It was championed by critics for its vision and courage, because the Cultural Revolution was still in full swing when the film was completed in 1974.

Tang remembers the enormous fallout that resulted from China Behind. It was banned in Hong Kong - a ruling that remained in force until 1987. The pro-Beijing press in Hong Kong, dismayed by Tang's depiction of the political situation in the mainland, accused her of being a Russian spy. These problems mirror the difficulties she had in making the film, when she decided to shoot on location in Taiwan - then ruled by the authoritarian Chiang Kai-shek.

'You're not allowed to bring in even a Mao button,' Tang says. 'But I did that and more - I brought the flags, the uniforms, everything that would amount to treason there. And then you have students who refuse to dress up as communists, sailors who refuse to wear 'all these commie uniforms', and it's hard to teach the children to sing all these revolutionary songs they haven't even heard of.'

Given the context in which it was made, China Behind was viewed by many - especially those who haven't watched the whole film - as a partisan tract against the communist regime in Beijing. Tang still finds it ironic that some would champion her as an anti-communist hero. She readily admits that, far from being an ardent opponent of communism, she was quite sympathetic to the political ideals in mainland China.

'In those days, young people were very much drawn to what was happening in China,' says Tang. 'You want to be part of it, to help construct the nation. You have the foreign press and the propaganda coming out of the country saying very favourable things about it. But then when we were reading all this you see people swimming to Hong Kong, when all we wanted was to swim in the other direction.' As doubts began to cloud her initial enthusiasm towards the campaign, she started interviewing refugees and reading in-depth documentation about events on the mainland.

China Behind wasn't solely about the horrors of the Cultural Revolution. In the story, Hong Kong offers no comfort to the protagonists. Alienated by the city's greed-driven capitalist system, they are again marginalised as outcasts, just as they had been on the mainland.

According to Tang, such existential crises have been the cornerstone of her films. 'It's the recognition of us human beings living in this world, going through all the trials and tribulations,' she says. 'Everything is so much to endure for every one of us, like the helplessness we see in the films.'

However, pioneers are often fondly remembered only in retrospect. In the 70s, the film industry in Hong Kong distrusted women and academy graduates. Tang was both, having graduated from the University of Southern California in 1964 and worked as a director of commercials before returning to Hong Kong. 'When you came from a film school you were very much derided,' she says. 'They'd think: 'So you think you know better? What have you done?' It wasn't easy because everything you do is very different from the established way of doing things. You didn't have any track record and it's very difficult to push your way around. And you have an extremely limited budget, which is probably a fraction of their budget.'

The Arch, Tang says, was made with the budget of a cheap film, and shot in only a few days. However, she spent 48 days shooting alone. Tight resources didn't hinder her efforts. A film about the painful lengths a widow goes to in order to uphold the reputation of her late husband's family name, The Arch won awards and acclaim around the world, and was shown at the Cannes Film Festival in 1970.

For Tang, these were happier times. The more she engaged with local cinema, the more entangled she became in the convoluted politicking and posturing that marks show business as a world of its own. Her third film, the gambling-oriented Sap Sup Bup Dub. was heavily cut against her will. The Hong Kong Tycoon, her final movie, involved frantic on-set rewriting which Tang says she found unsatisfactory. 'I was given the scene [on set] and told to shoot it - but it was unusable, so I had to rewrite and correct it right on the set. How can you work like that?' Tang didn't even see the finished cut. By then she had already moved to Los Angeles.

Her decision to retire from filmmaking was vindicated by her experiences on Peking Encounter, an American television movie made in 1981 about a love affair between two expatriates in Beijing. She was approached by a producer who had seen her work, and asked to write the screenplay and direct the film. She did the former but declined the latter because it was more 'a film about Caucasians'.

It's a decision she still regrets. 'They promised me somebody who really understood China would take over the directing job,' Tang says. 'They said, 'You'll be so happy, the director has been to China'. Then I found out that when he arrived in Beijing he was a sailor during the Korean war and was on a boat passing by or something. And he couldn't even pronounce Mao.'

That Robert Altman was second-unit director and the then-unknown Joan Chen was making her last appearance before moving to the US are no consolation to Tang. 'I went to the shooting and I couldn't bear it. So the American producer said, 'Just take it easy, I'll take you shopping. Don't even bother with them.' I was used as an entree into the Chinese market. So that was enough - my last attempt,' she says.

Little did she know that, years after thinking she was rid of filmmakers, they would return as her customers. 'Chinese cuisine isn't really very well represented in America,' says Tang. 'Chinese restaurants here are even less than theme parks - they're just very crude presentations. The service is very sloppy and the decor is usually very, very unimaginative. Even their names are extremely stereotyped. I don't think that's all we can offer.'

China Behind, Aug 17, 7.30pm, Hong Kong Film Archives, 50 Lei King Rd, Sai Wan Ho. $30, Urbtix. Inquiries: 2739 2139