Later, he went to study at Chinese Geology University majoring in precious stones and mineralogy. Before he found a job, he became rich again, thanks to his overseas relatives who didn't have offspring themselves and left their entire fortune to him when they died.

Unlike some newly-affluent Chinese people who invest in antiques and art, Zhang has always treated collecting as a hobby.

Over the past two years, Zhang has provided free technical support for the Beijing Watch Factory (BWAF).

Zhang participated in the designing of "Playing Dragon & Phoenix", a tourbillion wristwatch, which was displayed at the Basel World Watch & Jewellery Show in 2006.

It is the first watch to feature engraved patterns on both surfaces of the main plate, bridges and the wheel's spokes. Later that year, the watch was sold for 1.08 million yuan ($125,000).

"Zhang is a godfather-like figure in many fields. Watches are just one of them," BWAF general manager Miao Hongbo says.

"Although he is not a professional watch maker, he has comprehensive knowledge in this regards, and he even knows some things our experts don't know."

Under Zhang's supervision, the factory last month produced a tourbillion minute repeater, which has only previously been made in Switzerland and Germany.

Zhang has also collected more than 200 katydid or cricket containers, which were popular among rich officials between the Qing Dynasty (1644-1911) and the early years of the 20th century.

"It's a dying culture, but I believe it is worth collecting to help younger generations who might otherwise never know about the past," he says.

There is no need for him to stroll around antique markets to spot treasures, as people automatically come to him for business, or he entrusts agencies to bid on his behalf for treasures in domestic and overseas auctions.

His favorite treasure, surprisingly, is a homemade pen cap, a gift from his fourth aunt.

"When I entered a primary school, I got a pair of Parker pens. So, my aunt used my father's riding boots to make the cap by her own hands," he says. "It reminds me of her love, which is priceless."

Despite having the kind of wealth that many people dream of, Zhang says his life isn't perfect.

"I feel lost," he says with a great sigh. "Getting obsessed with one thing is a way to conflict with reality."

As a billionaire, Zhang's lifestyle is surprisingly simple. He doesn't watch much TV, preferring to read when his friends are not around; he isn't a party animal, and never celebrates his birthday; he shuns extravagant clothes, and didn't allow his wife to wear fur. He has no luxury furniture at home, and the bedstead he has been using since his wedding was made from an abandoned tank for goldfish.

"When you have nothing to fight for, life can be very simple, and you should create your own culture," he says.

Now, he is learning to fly his private fixed wing plane.

Zhang says that he will donate all of his treasures to the country after he dies, "at least they will be looked after in a better way."

"Even though you have a lot of land you only need a small hole in the ground to rest forever. Money is just a number," he says.

(China Daily April 2,2008)