It is called sushi, but there is no vinegar in it anywhere. A ball of rice — barley rice, in the old versions, not white — wrapped in a single lightly pickled takana leaf, and nothing else at all. The originals were the size of a softball. You hold one in both hands and open your mouth wider than is comfortable in company.

Nobody agrees on where the name came from. One account says that opening your mouth that wide makes your eyes open with it. Another says the things were so large and so good that people's eyes widened at the sight of them. A third points at the leaf, wrapped to seal the rice completely, and borrows an old word for sealing a gap. The three explanations sit side by side in the local records, unresolved and apparently content to stay that way.

This was working food, carried into the cedar forests and onto the boats of the southern coast. The leaf is the container, so hands black with resin or silver with fish scales never touch the rice. It was designed by people with no water to wash in.

Kumano is steep and wooded and it rains there constantly. Standing on a wet slope with the mist coming up the valley, unwrapping one of these and finding it still faintly warm inside its leaf, you understand why they were made so large. Lunch had to hold until dark.