Hiyamugi are thin Japanese wheat noodles . They are between 1.3 millimeter and 1.7 millimeter in diameter, and anything thinner is somen noodles, while anything thicker is udon. These delicate noodles are traditionally enjoyed cold during hot summer months.
Hiyamugi are often served over ice or floating in cold water. They're usually accompanied by tsukejiru dipping sauce on the side, consisting of soy sauce, mirin, and dashi. The noodles are sometimes garnished with spring onions, ginger, or sesame seeds.