Jongno is home to a number of famous haejangguk restaurants, and Cheongjinok (청진옥) is considered the forerunner among them. Opened in 1937, the restaurant has been run by three generations of the same family. Beef bones are simmered for more than 24 hours to make a rich broth, and soybean paste is added to neutralize the meaty odor. Ingredients added to the broth include various vegetables, clotted beef blood, beef intestines, and rice. Always crowded, Cheongjinok is open 24 hours a day.