Soybeans soaked overnight are boiled until they are just short of soft, then ground down in a suribachi or a stone mill. The paste goes into a pot, is seasoned with soy sauce, and is brought almost to the boil. That is all of it.

Nothing else goes into the pot. No vegetables, no meat, not even the tofu that the beans might have become. The only additions are at the table, where chili powder is the usual thing, with wasabi or yuzu kosho as alternatives.

It belongs to Shirakawa village, deep in the mountains, where soybeans were the reliable source of protein and were turned into miso and into tofu because there was little else to turn.

This soup is said to have emerged from the tofu-making process rather than being devised on its own. It was food for the days that counted: celebrations, and the hoonko Buddhist observances. It spoils quickly in warm weather, so it is eaten from autumn through winter and into early spring, which in a village buried in snow is most of the year that anyone is indoors. It is also called suritate-jiru, or dobu-jiru, depending on who is speaking. Beans and salt, and nothing else at all, and what comes out of the pot is a soup.