Visits are by appointment and take about an hour. Noda has soy sauce works, brick storehouses and the former residences of brewing families within the town, and the fermenting and pressing stages can be seen on a tour. Admission is free but booking is required in advance, and the visit runs as fifteen minutes of film followed by about forty-five minutes walking through the plant itself.

You are taken past moromi at various stages of maturation and can check the colour and the smell, which is the part that makes the process concrete: flavour is not being added at the end, it is developing in those tanks over months. A goyōgura, a small traditional brewhouse, stands on the same site, so an industrial plant and a hand-scale brewery are operating a few metres apart from each other and can be compared directly. The Tōbu line reaches Ōmiya and Kashiwa, and employment in food manufacturing is concentrated in this city, so a good many households here have some connection to the industry the tour is showing you.

Soy sauce from the factory and soy sauce from the brewhouse are made the same way. The ingredients are identical — soybeans, wheat, salt, kōji — and so is the order of operations: ferment, mature, press. What differs is the scale and the degree of control, and neither of those is a difference in principle. Book the tour and spend the hour, and the point stops being theoretical and becomes visible: the same process, running side by side on one site, at two sizes that look nothing whatever alike and produce the same thing.