In Korean cuisine, red bean soup is called patjuk (팥죽), and is commonly eaten during the winter season. On Dongjinal, a Korean traditional holiday which falls on December 22, Korean people eat Donji patjuk, which contains saealsim (새알심) meaning bird egg, a ball made from glutinous rice flour, named such due to its resemblance to small bird's eggs, possibly quail eggs.
In old Korean tradition, patjuk is believed to have a mysterious power to drive evil spirits away. According to Korean traditional folk beliefs, the color "red" is a symbolic color of positive energy which can defeat negative energy. Cooking and eating patjuk is a ritual to prevent bad luck, epidemic disease, and comes from evil spirits. Before eating the dish, Korean people used to serve it their own house shrine, they scattered it all around the house like in the kitchen, storage house, gate, yard and so on. These customs have been handed down through Chinese mythological stories. According to Hyungchosesigi, there was a man named Gong Gong. He had a bad son, and after he died he became a god of epidemic disease. Because of his cruel temper, a lot of people were killed by epidemics. Trying to find a solution to prevent infectious diseases, they recalled the fact that the son of Gong Gong hated "red bean soup" when he was alive. Thus, people made red bean soup and scattered it all around the house. And then the epidemics disappeared. Since then, patjuk has been the food that all spirits hate.
Eating patjuk is a ritual to wish for abundant harvests. Ancient Korea was an agrarian society, and a rich harvest has always been a pivotal issue for them. Koreans eat Patjuk (red bean soup) on Donggi(winter solstice), when the days start becoming longer than nights. When they make Patjuk (red bean soup) they add small dumplings which were made of rice as the same number as their age. By fully relaxing and eating nourishing health food, they wanted to have a preparation period before starting farming in the spring.
Patjuk embodies a custom of conserving food. Koreans usually eat rice and side dishes. However, in the wintertime when Korean families had shortage of grains, patjuk became a complete meal itself. It could be made of simple ingredients. For example, red beans, water, small grains of rice and also it requires no need extra side dishes. Thus, when people prepare some events in winter, patjuk is an economical food for conserving grain.