Dangmyeon is the Korean name for the sweet-potato-starch noodles used in japchae.
These translucent noodles are made primarily from sweet potato starch. After cooking, they become chewy and glass-like, making them well suited to absorbing the savoury sauce used in japchae, a Korean dish of noodles stir-fried with vegetables and often meat.
Dangmyeon is also called Korean glass noodles, although the term “glass noodle” can refer to several starch-based noodles across East and Southeast Asia. Unlike mung-bean glass noodles, dangmyeon is characteristically made from sweet potato starch.
Japchae was historically a royal-court dish, but it later became a widely served Korean celebration food. The noodles are commonly seasoned with soy sauce, sesame oil, garlic, and sugar.