It seems there are two kinds of Korean soups. Some of them are '국', such as 미역국, 콩나물국, 배추국. But then there are also '탕', such as 갈비탕, 삼계탕. Some even seem to have two names, e.g., '우거지국' & '우거지탕'. What is the difference between '국' and '탕'?
They are similar dishes. For example, here are pictures of two Korean dishes:
- 돼지국밥 is probably the most famous dish from Busan: it is a soup (국) containing pork (돼지) and rice (밥) as main ingredients.
- 돼지국밥 is similar to 설렁탕, except that the latter is made with ox meat and is a Seoul dish.
Honestly, I can barely see a difference from the pictures.
The 탕(Tang) page on Wikipedia redirects to the 국(Guk) page. According to that page,
Guk(국), also sometimes known as Tang (탕), is a class of soup-like dishes in Korean cuisine. Guk and tang are commonly grouped together and regarded as the same type of dish, although guk is more watery and a basic dish for the Korean table setting, and is usually eaten at home; tang has less water than guk and has been developed for sale in restaurants.
There is more information on the Wikipedia page:
- As often in Korean, one word has a native Korean origin (국) while the other has a Sino-Korean origin (탕). 탕 (as many Sino-Korean word I think) has been used as a honorific form of 국.
- Some dishes seem to be known with two names, like 곰국/곰탕, but 국 and 탕 are not interchangeable. In particular, 감자국 is made from potatoes (감자) while 감자탕 contains pork bones and potatoes.
Note: The Korean Wikipedia seems to confirm the English version: the dis-ambiguity page for 탕 describes it as "국의 높임말" ("국's honorific form") and the 국 page has "국또는 탕은 밥과 함께 먹는 국물 요리" ("Tang, as well as Guk, is a soup eaten together with food") for first sentence.
나머지는 내가 준비할 테니 가서 탕을 좀 내와라.
means the same as
나머지는 내가 준비할 테니 가서 국을 좀 내와라.
However when they are used to incidate specific dishes, they do have a slight difference in meaning. According to 표준국어대사전, the suffix -탕 is used to mean 국 which has a rich taste due to being cooked for a long time. That makes sense since most dishes with 탕 at the end of their names are made with different kinds of meat, and cooked for a long time to enrich their tastes.