A Hong Kong bartender-turned-feng shui master who says he is the sole heir to the 13 billion dollar estate of Nina Wang testified Wednesday in the epic court battle over the eccentric tycoon's fortune. Tony Chan appeared on the witness stand more than six weeks into the court battle over Wang's estate in a case that has gripped the tycoon-obsessed city. The trial will decide whether Wang, who at one stage was Asia's richest woman, left her entire fortune to Chan when she died of cancer in 2007 at age 69. Opposing Chan's claim is Wang's Chinachem Charitable Foundation, which is now controlled by her siblings, who say a will awarding Chan the huge fortune is a fake. Lawrence Lok, the lawyer for Chinachem, started his cross-examination in front of a packed courtroom Wednesday by questioning Chan's credibility. He asked why biographical information on Chan for an American college's fundraiser in Beijing showed he had received tertiary education in Canada, when in fact he had left school before university. The biography said Chan returned to Hong Kong in the early 1990s to take over his family business and assets. Chan told the court that the information was wrong, but that it did not come from him. He said he had neither the money nor the time to study overseas. 'I didn't claim myself to be anything for that function,' he told the court. The feng shui master, 49, told the court that since leaving school he had been a bartender, machinery salesman, a waiter in a bakery chain and a market researcher. He set up a company trading computer parts in China in the early 1980s which closed down around 1988. He remained unemployed until 1990, the court heard. Wang left an estate estimated to be worth up to 100 billion Hong Kong dollars (12.8 billion US), although the exact sum remains difficult to assess. In her last few years, Wang became increasingly fascinated with feng shui, an ancient Chinese system that claims to harness natural energies and is widely used by Hong Kong residents. The case has filled the front pages of Hong Kong's media for weeks, and some reporters even queued overnight to secure a seat in the public gallery for the first day of Chan's testimony. 