Japchae, jabchae, chapchae, chop chae, or chap chae (Korean: 잡채) is a Korean dish made from sweet potatonoodles (called dangmyeon, Korean: 당면), stir fried in sesame oil with vegetables (typically thinly sliced carrots, onion, spinach, and mushrooms), sometimes served with beef, and flavoured with soy sauce, and sweetened with sugar. It is usually served garnished with sesame seeds and slivers of chili. It may be served hot or cold.
This dish is served at Korean parties and special occasions, with seasonal vegetables added.
Japchae is most commonly served as a side dish, though it may be a main dish. It is sometimes served on a bed of rice; with rice it is known as japchae-bap (잡채밥), bap (밥) meaning "rice." (from Wekipedia)