Gao was severely beaten and kept under house arrest by the casino's owners for a week.

He was allowed to leave only after he helped win a large sum of money for the boss.

"You can never be too careful as a cheat," he said philosophically. "A gambler will lose his money, a cheater can lose his life."

The incident proved a turning point for Gao, and from then on he was on a mission to guide other gamblers.

Last year, he rented a 30-square-meter unit on a commercial street in Shenyang and redecorated it as a mock casino with mahjong, roulette, craps and baccarat tables.

With funding from past clients, including many successful entrepreneurs, Gao was able to expand his space to more than 200 square meters in August, and he plans to expand it even further in May next year.

He also has all the latest gadgets for cheaters - high-tech contact lenses, belts and rings - thanks largely to his connections with overseas casinos.

"I was crazy when I gambled," said Li Xiaoliang, who kicked the habit in October.

The 28-year-old said he lost all his possessions and almost divorced, adding: "I always told myself I could win it all back."

He recalled stumbling across Gao's casino one night, and thinking it was real, went in to try his luck.

What he saw changed his life.

"I was surprised to see all the tricks. It was a real wakeup call," said Li, who now volunteers at the mock casino.

"I realized I'd been so foolish, and I promised myself that I wouldn't be fooled again. Both my family and I are grateful to Gao."

Although some critics have questioned Gao's technique, including some who suggested that he is simply teaching old dogs new tricks, the ex-professional gambler insisted: "What I do is just a performance. I do not teach them how to cheat. All my tricks take one to two years to learn."

Gao's efforts have also put him in danger.

He has had to hire four bodyguards and seldom goes out to parties, for fear of being confronted by people in the underground gambling industry.

To protect his daughter, she has his wife's surname, which is unusual in Chinese culture.

Despite the risks, he carries on, although his main income is still from investments he makes in his friends' construction projects.

"This way, I can support my family and have enough time to run a casino," he said. "It's a win-win situation."