Sau, very possibly the best Chinese chef in Boston, began learning how to use his hands at 13, when he went to work in his father's restaurant in Hong Kong. (His father had learned to cook in his father's restaurant in Shanghai.) For a year, Sau says, smiling slightly, he chopped onions and ginger, only that. Then, for three years, he made only noodles and rice.

"Chinese cooks learn by watching," Sau says, and often head chefs would try to hide their secrets, so mastering the intricacies of the vast repertory of 4,000 years of Chinese cuisine meant paying close attention for a long time. "I've worked 36 years {as a chef} and know only 90 percent," Sau says. "I'm not yet perfect."

Chinese food is all about differences, distinctions in regional tastes, which can make cooking in Chinatown here difficult. "You have to make each dish right." He and Jackson Cheung, co-owner and manager of New Shanghai, explain that customers from many regions of China come in to the restaurant. The waiters and waitresses will "clue in the chef," Cheung says, as to whether the customer is originally from Shanghai or Beijing or the Szechuan region. "Even though the dish may be the same, I will try to make it in the Beijing or Shanghai style," says Sau.