My parents returned to the stall often. Then, one day, Lao Zheng disappeared. Some said he'd retired, others that he'd sold his stall to pay gambling debts. Eventually, my parents discovered that a couple by the last name of Luo had purchased his recipe. Today, the shop that they opened, called Yong Kang Beef Noodle, is one of Taipei's most famous restaurants. The Luos were avid pupils of the old man's techniques. They'd learned how to introduce specific ingredients at different cooking intervals, to slice the shank into tender wedges against the grain, and, as Lao Zheng did, to keep the recipe a secret.