Southern water chestnuts are actually water chestnuts. There are also water chestnuts in the north. They are the rhizome of an aquatic plant. They are generally sold in farmers’ markets. There are also canned water chestnuts with the skin removed in supermarkets. There are many places to make the dish you mentioned. Even if it is cooked, it is still very green. It is used in Sixi Meatballs mainly to clear the mouth.