Many people regard mulnaengmyeon, the buckwheat noodle soup served in a chilled beef broth with pickled radish, sliced Korean pear, and a hard-boiled egg, as the specialty of Pyongyang, and bibimnaengmyeon -- noodles flavored with a spicy red pepper sauce -- as the specialty of Hamhung Province. But the two cold noodle dishes are actually categorized according to their place of origin. Mulnaengmyeon noodles are made of buckwheat and bibimnaengmyeon noodles out of corn starch.
Chilled buckwheat noodle soup dates back hundreds of years. In a book about seasonal customs titled "Dongguk Sesigi" written in 1849, the chilled noodle dishes from Pyongan Province are described as the best to eat in the winter. The popularity of the dish can be attributed to the difficulty of rice farming in the north due to the harsh climate.
Noodle dishes became a favorite food to satisfy midnight cravings for northerners, who ate dinner early in the evening as the days became shorter.
It became popular in the South in the early 1920s. At that time, it was mainly sold in Seoul's Nakwon-dong and Gwangyo neighborhoods. It became more widespread after the Korean War when refugees from the north headed south. According to a popular comic book, "Shikgaek" or "Le Grand Chef" by cartoonist Huh Young-man, the soup was considered a high-end gourmet dish during the early 1960s when a serving of bulgogi (barbecued beef) cost W60 and a noodle dish W35.