Before machine-made noodles became common it was possible to distinguish somen noodles from hiyamugi noodles because the cross-section of the somen noodles was round due to the fact that the dough was made thin by the hand-stretching process, and the cross-section of the hiyamugi noodles was square because the dough was flattened and then cut into narrow strips.
機械麺が一般化する以前は、素麺は手延べ工程により生地を細くするため断面が丸く（●）、ひやむぎは生地を薄く打ち伸ばしてから細く切るため断面が四角（■）になっている、という見分け方も出来た。