Horse mackerel or sardine, filleted, with miso and spring onion and shiso and ginger or myoga piled on top. Then it goes onto the board and gets chopped with the knife, over and over, until the whole mass turns sticky and holds together.

This belongs to the coast of the Boso peninsula, where the Kuroshio runs close in. Fishermen made it out on the boats, and it has a second name that means offshore namasu. On a moving deck, with no bowl and nowhere to put one, this is the shape a meal takes: everything happens on one flat surface, with one blade.

The usual name is said to come from that stickiness. Another account has it that the dish is good enough to make you lick the plate, which points at the same word from the other direction. Either way the name is about what stays behind on the surface.

Cook the chopped mixture and it becomes something else, sanga-yaki. It can go straight onto a griddle or a grill, or be packed into a scallop or abalone shell first, or wrapped in leaves. One explanation of that name says fishermen grilled it up at mountain huts, so it was the mountain-house version. A dish invented on the water is named after a shed on a hillside, which tells you how far inland these fish were being carried.