2. Clean the pig hair on the surface of pig's trotters, rinse it with clear water and cut it into small pieces. If it's hard to cut at home, it's best to let the butcher shop cut it when you buy it.
3. Put the chopped pig's trotters into a pot with cold water and bring to a boil. After boiling, add appropriate amount of cooking wine to remove fishy smell, and cook for about five minutes. After cooking, take it out and drain it.
4. Wash the pot, heat it on high fire, add appropriate amount of vegetable oil, and when the oil is 60% to 70% hot, add rock sugar and stir fry. Rock sugar will melt at high temperature and turn brown slowly.
5. Stir-fry the trotters, let them be colored, then add yellow wine and soy sauce, stir-fry the star anise.
6. Add water without trotters, add ingredients, boil and simmer for about 90 minutes.