Japan — nori cultivation in Tokyo Bay since Edo period; Ariake Sea nori farming established in Meiji era; aonori cultivation primarily in Mie and Tokushima Prefectures
Japan's seaweed culture extends far beyond the nori sheet used in sushi. Aonori (green laver, Ulva and Enteromorpha species) is dried and powdered or flaked and used as a finishing seasoning: sprinkled over okonomiyaki, yakisoba, takoyaki, and fried preparations, it adds a distinctive oceanic green-tea-like aroma. Nori (Porphyra tenera) exists in multiple forms: the roasted sheet (yaki-nori) for sushi and onigiri wrapping, the dried whole sheet (hoshi-nori) for soup, and ajitsuke-nori (seasoned nori) for breakfast rice accompaniment. Beyond these, Japanese seaweed culture includes: ao-nori, wakame (for miso soup and salad), hijiki (iron-rich black strands for cooked preparations), and kombu (as primary dashi ingredient and edible after cooking).
Nori: toasted, oceanic, umami-rich with subtle sweetness; aonori: fresh, herbal, green-ocean aromatic; both add marine dimension and visual colour contrast
Nori is moisture-sensitive: exposure to air begins to soften yaki-nori within minutes. For sushi and onigiri, nori must be perfectly crisp at the moment of contact with rice — wrap just before eating. Store in airtight containers with silica gel desiccant. Aonori is fragile and its aromatic compounds volatile — add as the very last step before serving. High-quality aonori from Tokushima Prefecture has a vibrant green colour and intense fresh sea aroma; inferior aonori is khaki-coloured and smells of dried fish rather than fresh ocean.
Re-crisp slightly softened nori sheets by passing briefly over a gas flame (both sides) — 3–5 seconds per side on medium-low flame restores the crunch. The best nori comes from Ariake Sea (Saga and Fukuoka Prefectures) — premium 'first harvest' nori from November–December is the most prized. Nori quality grade is determined by colour (deepest blue-black is highest grade), uniformity, and the presence of holes. Learn to distinguish nori quality by holding a sheet to light — premium nori should be uniformly dense with no pinhole transparency.
Using soft, stale nori — the texture is as important as the flavour. Storing opened nori without proper sealing, accelerating moisture absorption. Applying aonori early in cooking, which destroys its volatile aromatic compounds. Treating all seaweed interchangeably — wakame, hijiki, kombu, nori, and aonori have completely different textures, flavour profiles, and appropriate applications.
Tsuji, Shizuo — Japanese Cooking: A Simple Art; Hosking, Richard — A Dictionary of Japanese Food