Somen is a thin noodle made of wheat flour, the noodles are so thin they are less than 1.3 mm in diameter. The thin noodles are popular across East Asian cuisine, in Japan, they are called Somen, in Korea, they are referred to as Somyeon, while in many parts of China they are called Sumian. The Japanese Somen is made very carefully by stretching the dough with vegetable oil, forming thin strands. These strands are air-dried and preserved for later use. One must understand that Somen are different from hiyamugi which is knife-cut and not hand-pulled.
In Japan, Somen is generally served cold (room temperature) with a light dipping sauce called tsuyu. If it is served hot, it would be called Nyumen, which is a Japanese name for a version where these thin noodles are served warm in soup, and eaten in winter, just like soba or udon. Coming to tyusu, this dipping sauce is a katsuobushi-based sauce that may be flavored with onion, ginger, or myoga.
