Somen is the Japanese noodle made from thin wheat dough and traditionally served chilled with dipping sauce.
Somen noodles are made from wheat flour, water and salt. Their defining feature is extreme thinness: Japanese standards generally classify somen as noodles less than 1.3 millimeters wide. The dough is stretched, often with vegetable oil, before the strands are dried.
They are especially associated with summer because they are commonly chilled and eaten with a light soy-based dipping sauce called tsuyu. Garnishes may include grated ginger, scallions and sliced vegetables. Nagashi-somen, in which noodles flow through a bamboo channel of water, is a popular seasonal activity.
Somen is made from wheat, so it is not gluten-free. It is also different from soba, which is based on buckwheat, and udon, whose strands are much thicker.