Yudu is on the 15th day of the 6th lunar month. As part of the hottest period of the summer (Sambok), people enjoy ginseng chicken broth and other healthy soups. This custom is called Yudu.
Offering the first harvest of the season to the gods is the main tradition of Yudu. As the new harvest starts to grow during the Yudu season, households use this day called Yuduchunsin to gather Yudumeyon, Sanghwabyeong, Yeonbyeong, Sudan, Geondan, various wheat, and fruits to offer a sacrifice to spirits. In addition, people visit a clean stream to wash their hair and body on this day. This custom is believed to chase away bad spirits and help avoid suffering from heat during the summer.
During this day, people eat Yudumeyon, Sudan, Sanghwabyung, and many other dishes. Everyone enjoys Yudumeyon this day, for its superstition of prolonging life and chasing away the midsummer heat. Yudumeyon, which is usually made of flour, can also be made with malted rice and be called Yudu Soup. It is said that if it is made into three marble shaped balls, dyed with various colors, and hung on household doors with strings, disasters will be prevented.
Sudan and Gundan are made by cooking rice powder, cutting them into long thin slices, rolling them into little marble shaped balls and then soaking them in honey. When they are eaten with ice water it is called Sudan; it they are not, it is called Gundan. Sanghwabyung is a dish made by kneading water with soybean flour, adding sesame, soaking it in honey and cooking them all together.