Naengguk
Naengguk () or chilled soup refers to all kinds of cold "guk" (국, soups) in Korean cuisine, mainly eaten in summer. It is so called "changuk", which literally means "cold soup" in pure Korean, while the term "naengguk" is a combination of a hanja word and a pure Korean word with the same meaning. The first historical record on "naengguk" appears in a poem written by Yi Gyu-bo (1168–1241), a high officer of the Goryeo period (918–1392). In the poem, "naengguk" is referred to as "sungaeng", which literally means "sunchaeguk", soup made with "sunchae" ("Brasenia schreberi"). Yi praised its  clear and plain taste, saying it made usual dishes seem vulgar. "Naengguk" is largely divided into two categories according to seasoning and ingredients. The first category is made by mixing chilled water and vinegar to give a sour and sweet taste such as "miyeok naengguk" made with wakame, "oi naengguk" made with cucumber, "pa naengguk" made with spring onions, "nameul naengguk" made with garlic, and "gim naengguk" made with "gim" or nori. The other category is made to supplement health and has rich tastes such as chilled soup made with chicken, sesame, or soybeans.