Kombu has been harvested from the cold waters around Hokkaido since antiquity. The island's cold, nutrient-rich Pacific waters produce kombu with exceptional glutamate concentration. Three primary production regions produce distinct grades: Rishiri (Rishiri Island, northern Hokkaido) — the most delicate, pale dashi; Rausu (eastern Hokkaido) — fuller, more robust flavour; Ma-kombu (southern Hokkaido coast) — the most widely available, excellent all-purpose grade. [VERIFY] Tsuji's specific kombu grade recommendations.
Kombu (Saccharina japonica, kelp) is the glutamate-rich dried seaweed that forms one half of the dashi foundation. Its flavour is not seaweedy in the way that dried nori or wakame is — it is deeply savoury, clean, and almost invisible in the finished dashi while being entirely responsible for its character. Selection matters absolutely: the grade of kombu determines the flavour of every dish that uses dashi, which in a Japanese kitchen means almost everything.
Further training content for this entry is being completed.