Hot and sour soup is a popular example of Chinese cuisine. Although it is often said to have originated in Sichuan, this is actually a variant of hulatang or "pepper hot soup" (胡辣汤) with added vinegar to enhance the sourness. This variation is found Henan cuisine. Also popular in Southeast Asia, India, Pakistan and the United States, it is a flexible soup which allows ingredients to be substituted or added depending on availability. For example, the American-Chinese version can be thicker as it commonly includes corn starch, while in Japan, sake is often added.
