Nori, toasted seaweed in sheets
What it is
Nori is a red seaweed that's chopped, spread into paper-thin sheets, dried and then toasted. Nori species used to be placed in the genus Porphyra, and today in Pyropia. The most widely farmed is susabinori. Asakusanori, which gave its name to the nori of Edo, is rare today: in Japan it's listed as an endangered species.
Where it comes from
In Japan nori has more than 1,300 years of written history. The Taihō Code, which came into force in 702, lists it among the sea products used to pay taxes. That's why 6 February, the day that date corresponds to, is Nori Day. The sheets as we know them were born in the Edo period. The story goes that in Asakusa, where recycled paper was made, the same technique was used to spread out the chopped seaweed: hence the name asakusa nori.
The Mother of the Sea
Until the mid-twentieth century the harvest was uncertain, because nobody knew where the spores came from. In 1949 Kathleen Drew-Baker, a botanist at the University of Manchester, discovered that a tiny alga living inside seashells is one stage of nori's life. Professor Sokichi Segawa brought the discovery to the Kumamoto Prefecture research centre, which in 1953 managed to seed nori for the first time. In Uto, on the Ariake Sea, farmers put up a monument to her in 1963: they call her the "Mother of the Sea".
Where it's made
The best-known area is the Ariake Sea, in Kyushu. Saga Prefecture was Japan's top producer for years and went back to first place in 2025.
In ramen
In iekei ramen, born in Yokohama in 1974, nori is a signature: usually three sheets on the rim of the bowl, with spinach and chashu. Add it at the end, standing up against the rim. The part outside stays crisp; the part in the broth softens and, little by little, gives the broth depth, with a light scent of the seashore. Once you've opened the packet, close it tightly: nori picks up moisture and loses its crunch.
