Sappa, a small member of the herring family, is scaled and gutted, salted, and then steeped in vinegar with fresh ginger, chilli and a strip of kelp. Left long enough in the vinegar, the bones soften and the whole fish can be eaten head and all, without anything being removed at the table. It is oily, sharp and about the length of a finger, and it costs almost nothing.

The name comes from a phrase meaning to borrow rice. The fish was said to go so well with a bowl of rice that you would run out and have to borrow more from the house next door. A diary from 1869 puts the same story on the water instead: fishermen borrowing rice from the neighbouring boat. The setting shifts from house to boat; the point of the story does not move at all.

In the Inland Sea this fish came up in quantity. It was cheap and it spoiled fast, which meant the choice was never whether to pickle it but how soon.

For festivals and family celebrations it is turned into sushi and laid over the rice. In that form, as mamakari-zushi, it appears on the national list of a hundred rural dishes worth keeping. The fish that was supposed to make you borrow rice arrives sitting on top of it.