Sōmen (素 麺) is a very thin, white Japanese pasta, made of wheat flour, less than 1.36 mm thick.
It is most often served cold. The difference between sōmen and the next pasta according to thickness - hiya-muga (noodles with ice) and even thicker udon noodles are mainly their size. The sōmen noodles are stretched at runtime just like some types of udon noodles. Sōmen is usually served cold with a mildly flavored dip or tsuyu. In summer, sōmen cooled with ice is a popular cooling meal. Sōmen served in a warm soup is called "nyūmen" and is mainly consumed in winter.