Kalguksu is the Korean noodle soup traditionally made with hand-cut wheat noodles.
The name literally refers to noodles cut with a knife. Instead of extruding or pulling the dough, cooks roll it into a sheet, dust it with flour and slice it into strands. The noodles are then cooked in broth, often with vegetables, seafood, chicken or clams.
Kalguksu is a broad family of dishes rather than one single fixed recipe. Regional versions use different broths and toppings, including anchovy stock, shellfish and spicy seasonings. The hand-cut preparation remains the defining feature.
Jajangmyeon is also a Korean noodle dish, but it is served with a thick black-bean sauce rather than as a conventional soup. Japchae uses glass noodles made from sweet-potato starch, while naengmyeon is characteristically served cold.