Japchae is one of korean favorite traditional dishes, it's a sweet stir fry noodle with vegetables and beef. Japchae often serve as side dish on korean house, if japchae serve only with rice in a bowl then call japchae-bap.
Japchae first time serve at 17century when prince Gwanghae, the king of Joseon Dynasty held a big party at his palace. Because the king so pleased with the dish then he awarded his lieges (same as Lord), Yi Chung, by promoting him to the position of hojo panseo (same as secretary of treasury).
At that time japchae only made by vegetable and mushrooms, the kind of vegetables is depend on the seasonal vegetables at that time.
At early 20century japchae serve with dangmyeon, korean noodle which made by sweet potato.
Making japchae is quite easy but need special attention, vegetables, mushrooms and beef cooked separately to keep the flavor of each ingredients. Soy sauce, sesame oil and sugar give a savory and sweet flavor to the dish. The authentic flavor of japchae is sweet stir fried noodle, but you can always adjust the taste with your preference ;)