Menrui is the collective term for noodles in Japan. When a particular type of noodles are referred to, they are called men, which derives from the Chinese word mien or mian.
It is generally accepted that menrui was first introduced into Japan from China during the Nara period (710–94). The original menrui, however, seems to have been more like sweet dumplings than what we call noodles. (These dumplings were called konton, the word whose original meaning is ‘chaos’, presumably because they had no definite shape. This is the same word as the Chinese hun-t’un, now familiar as wonton. Later the name changed from konton to undon, and eventually udon.) It is not known when the transformation from dumplings to noodles took place. In any case, it must have been a gradual process.