Yamato Province (Nara Prefecture), Japan — somen production since 3rd century AD
Somen and hiyamugi are Japan's finest-gauge white wheat noodles, traditionally hand-stretched (tejime somen) through a laborious oil-stretching process that can take 2–3 days from initial dough to final dried noodle. Somen (under 1.3mm diameter) is strictly the summer noodle: served cold in iced water (hiyashi somen) with cold mentsuyu dipping broth, negi, and ginger; the most famous variety is Miwa Somen from Nara (Japan's oldest somen designation, made since the 3rd century AD), followed by Ibo no Ito from Hyogo and Ojika Somen from Nagasaki. Hiyamugi (1.3–1.7mm) is slightly thicker and represents a seasonal bridge. Nagashi somen — bamboo-flume flowing noodles where diners catch passing somen with chopsticks at ryokan restaurants — is the theatrical summer experience. Toso-no-kane (New Year morning somen) is traditionally eaten in some regions for longevity.
Pure wheat delicacy — neutral, slightly sweet; the flavour is in the textural elegance and the dipping sauce contrast; premium hand-stretched somen has a silky suppleness that mass-produced lacks
Cook somen in abundant boiling water (very short, 90 seconds for dried); shock immediately in cold water to stop cooking and wash excess starch; serve in ice water to maintain cold temperature and slippery texture; dipping sauce (mentsuyu) should be cold and slightly stronger than regular soba tsuyu to account for dilution from ice water on noodles; premium hand-stretched somen has a silkier texture and more delicate flavour than machine-made varieties.
Miwa Somen (from Nara) is the benchmark: three-year aged somen develops a silkier texture through continued gluten maturation during storage; serve somen in a wooden tub of ice water and let guests lift portions to their bowls; toasted sesame sauce (goma-dare) is an alternative dipping sauce that adds richness; somen is also excellent in nimono stews and hot soup in winter — its delicacy absorbs flavour well.
Over-cooking somen (it becomes mushy in seconds — test at 80 seconds); serving at room temperature (somen loses its characteristic cooling, slippery character); weak dipping sauce (cold somen requires assertive flavour); using mass-produced somen when premium hand-stretched somen would transform the dish; confusing somen with Korean-style cold noodles (mul naengmyeon) which are buckwheat-based and have entirely different texture.
Japanese Cooking: A Simple Art — Shizuo Tsuji