The Harima records go back a long way. A document held at Ikaruga temple in Taishi-cho contains an entry for the twenty-fifth year of Oei, which is 1418, mentioning saumen.

It became a real industry only in the Edo period, some centuries later. Around the Anei years in the 1770s the Tatsuno domain listed noodle-making as a licensed trade and encouraged it, and by the Bunka years, in the early nineteenth century, the domain had begun actively protecting and developing its local products.

The materials are simple enough: wheat flour, and salt from Ako along the same coast. The dough is stretched by hand, drawn out thinner and thinner, and hung outdoors to dry. Production runs from October through to April, and the noodles made during the very coldest part of that stretch are the ones held in the highest regard by everybody involved.

The same river valley makes soy sauce, and the brewing there also happens in winter. That is not a coincidence. Both trades want the same three things: clean water, salt within reach, and air dry and cold enough to work in. The valley supplies all three, and it produces two entirely different products out of them at the same time of year.