Nori is the dried seaweed product commonly used as a ramen topping. It is usually served as a dark green sheet, strip, or smaller piece placed alongside the noodles, where it contributes a crisp texture and savory, ocean-like flavor.
Nori is generally made from edible red algae in the genus Pyropia. The seaweed is shredded and rack-dried in a process resembling papermaking, producing the thin sheets also familiar from sushi and onigiri. Toasted nori, called yaki-nori, is especially common in Japanese cooking.
Nori is easy to confuse with other seaweeds. Kombu is a thicker kelp used mainly to make stock, while wakame is often served in soups and salads. Hijiki is another edible seaweed with a darker, more branched appearance. Ramen may include any of these in some variations, but the classic sheet garnish is nori.