Areas which flourished during the Edo period having a history of presenting its somen to bakufu (Japanese feudal government headed by a shogun) but lost its somen industry later due to the urbanization, lack of successors, degradation of water quality, rise of machine-production of noodles, and so on.
江戸時代には隆盛を極め、幕府などにも献上された歴史を持っていたが、都市化、後継者不足、水質悪化、機械製麺の興盛などの影響により産地が消滅した地域。