It grows in the current that produces the Naruto whirlpools, in water moving fast enough that the seaweed is never once still. That constant motion is credited with producing the texture: a firm, faintly squeaking resistance when you bite into it, quite unlike wakame taken from calmer water anywhere else.

The color of it is a vivid green, and there is a specific reason for that. Heating turns the red pigment yellow, and the yellow combines with the green pigment, and what appears is that particular shade.

After the harvest it is blanched, washed in cold water, drained, and then packed in salt. The stems are then removed, the water is pressed out of it, and what results is shiozo wakame, salt-cured, which is the form in which almost all of it travels away from here.

The harvest season runs from January through to March. Harvesting starts in the coldest part of the year and the wakame reaches tables as the first thing that tastes like spring. A document more than a thousand years old records wakame being sent from the province of Awa as tribute. What the whole thing amounts to is a strait with an unusually violent current, and a texture on the tooth that is a direct record of it.