Sand lance fry are simmered down in soy sauce, sugar and ginger until the liquid is gone. What comes out is brown and twisted, and it looks, unmistakably, like a handful of rusted nails. Kugi means nail, and that is where the name comes from. Nobody along this coast has ever tried to make it sound more appetising than that.

The season opens in the last days of February or the first of March. For the fortnight that follows, the towns between Kobe and Akashi smell of the same thing at the same time, because every household on that stretch of coast is boiling the same fish in the same sauce at the same hour. People here say that when you catch the smell of soy sauce caramelising, spring has started.

It began in fishing households. It stayed there a long time. It became a general domestic habit only from the late nineteen-sixties, and spread in earnest after about 1980, when a recipe put out by the Akashi fishing cooperative was taken up and adjusted, mostly by women, for kitchens rather than boats.

One day a year, a whole coastline cooks the same dish at once. Not many places still have anything like that, and fewer still have it fixed to a date nobody controls.