From late October into March, saury travel south from off Sanriku on the cold current, heading for the Kumano Sea to spawn. By the time they arrive they have been in moving water for months. The flesh has firmed, the fish are smaller, and a good deal of the fat has gone.

That last part is why they are used here. Everywhere else in Japan, the saury worth having is the fat one, grilled in September with the oil spitting into the fire. In southern Wakayama the prized fish is the lean one, at the end of its journey, because that is the fish that makes good sushi.

It is split open, gutted, salted, and then cured in vinegar, with each of the small bones taken out one at a time by hand. Juice from yuzu or daidai goes in underneath everything else as a background note. For celebrations the head is left on and the entire fish, nose to tail, is pressed down onto the seasoned rice.

It was made in every house for the autumn festivals, for the new year, and for the launching of a new boat, and it is still there on the table every January. I had assumed a fatty saury was simply a better saury. It had not occurred to me that somewhere would be waiting for the other one.