Cui Lijie has no official position with Imperial Pacific International Holdings, but everyone calls her Madame Chairlady. She deserves a title, since she holds two-thirds of the shares in the Hong Kong-traded company that has made her an unlikely billionaire.

Imperial Pacific owns Best Sunshine Live, the casino on the U.S. Pacific island of Saipan producing high roller betting numbers better than Venetian Macao. This week, Madame Chairlady bought $100 million of company bonds to help finance its $600 million hotel, under construction on the Saipan beachfront. The company still needs an estimated $200 million to complete the hotel, its opening pushed back from early this year to August, though its casino area aims to open next month. Cui’s son, Ji Xiaobo, has the title of project director, but he’s known as the mastermind of the company’s ambitious $7.1 billion integrated resort plan for Saipan that’s begun with a casino in a tourist shopping mall, opened in July 2015.

Cui and son have both come a long way from Harbin, a town tucked in the northeast corner of China above the Korean peninsula, to Saipan, the principal island in the U.S. Commonwealth of Northern Marianas Islands.

Cui’s road to Saipan began as a so-called “barefoot doctor” treating patients in the countryside as a teenager. Back in Harbin, a series of business ventures led to investing RMB20,000 (roughly $5,000 at that time) in an auto repair shop in 1988. In the early 2000s, working with her son, Cui diversified into property and then LED lighting, prompting a 2008 move to Jiangsu on China’s central coast where that factory was located.

Efforts to obtain Hong Kong stock market listings for that LED maker, a health tonic company and other mainland small businesses led mother and son to relocate to Hong Kong. While Ji joined the securities profession and then Macau junket promoter Heng Sheng Group along with his aunt Cui Limei, Cui Lijie focused on property and jewelry collecting. “She likes jewelry more than property,” Ji says.

A vacation trip to Saipan inspired Ji to seek a casino license on Saipan, assisted by his mother and aunt. As part of the family push, in 2013, Cui led the family’s takeover of First Natural Foods Holdings, later renamed Imperial Pacific, for HK$300 million ($38.7 million). That initial investment has blossomed into a holding the market values around $1.7 billion.

Cui now spends most of her time in Saipan because “Hong Kong has way too many people.” On Saipan, she enjoys photography and is an enthusiastic participant in Imperial Pacific’s community outreach efforts. Cui says she particularly enjoys programs aimed at helping the rural poor, as she did in China 40 years ago, before she was a billionaire.

With additional reporting by Xiang Wang