A main line running for tens of kilometers, with hooks hanging off it at intervals, each baited by hand with a single mackerel, sardine, saury or squid. That is longline fishing, and it is how the tuna landed at Nachikatsuura are caught. One fish at a time, on one hook.

Each tuna is bled and killed individually as it comes aboard, then held in water chilled to just above freezing. Not frozen. That distinction is the whole business here. Freezing would preserve the fish indefinitely and change its texture and color permanently, and the entire operation is arranged to avoid it.

It only works because the grounds are close. The Kuroshio current and its branches bring good fishing within a short run of the harbor, so the time between the hook and the dock stays short enough that ice water is sufficient.

The market runs its auction by sealed bid in the early morning, and buyers move fast because the clock is still running on every fish in the room. What strikes me is that the celebrated quality here is not the result of adding anything. It is an accumulation of things not done. The season runs January to May, and the cold months carry the fat.