Given the ingenuity of Chinese cooks, it should come as no surprise that there is an amazing variety of Chinese soup. However, there are two major categories. Thin soups are made with a clear broth, and cooked quickly, with the meat and/or vegetables added near the final stages of cooking, depending on their individual cooking times. Just as in the case of dashi, the Japanese clear broth, it is important never to overcook the broth for Chinese thin soups. On the other hand, you don't want to overcook the vegetables: the idea is to cook them just enough so that they will still preserve their distinctive flavor. 

By contrast, the ingredients for thick soups are all added together at once. The soup is cooked more slowly, giving the ingredients time to blend together. Cornstarch or tapioca starch is often added near the end of the cooking process as a thickener.  

Hot and Sour Soup is an example of a thick soup. A number of ingredients such as shredded pork and dried Chinese mushrooms (in northern China it is traditionally made with fresh chicken's blood) are simmered together to form a thick broth, perfect for those cold Mongolian winter nights. Another example is Shark's Fin Soup. Recipes for the famous banquet dish call for it to be made with a thick or "gourmet" stock (see below). Meanwhile, in Ken Hom's Chinese Cookery, the author points out that Chicken and Spinach soup is an excellent example of a thin soup. The vegetable (in this case, spinach) is blanched first, reducing the amount of time it will need to be cooked in the soup. Similarly, the chicken is also blanched ahead of time.