What is "somen"

n. thin, white, noodles usually served cold and accompanied by dipping sauce

are very thin white Japanese noodles made of wheat flour, less than 1.3 mm in diameter. The noodles are usually served cold. The noodles' diameter is the chief distinction between sōmen and the thicker wheat noodles hiyamugi and Japanese wheat noodles udon. Sōmen noodles are stretched when made, as are some types of udon noodles. The dough is stretched with the help of vegetable oil to make very thin strips and then air dried.

Sōmen are usually served cold with a light flavored dipping sauce or tsuyu. The tsuyu is usually a katsuobushi-based sauce that can be flavored with Japanese bunching onion, ginger, or myoga. In the summer, sōmen chilled with ice is a popular meal to help stay cool.

Sōmen served in hot soup is usually called "nyumen" and eaten in the winter, much as soba or udon are.