Nori

Nori is often used for Japanese food. For example, it is used for Onigiri, rolled sushi, Gunkanmaki of sushi and so on.  Nori is made by stretching the seaweed into a paper and then drying it.

Nori, 海苔

In addition, many Westerners do not have enzymes that digest seaweed. So they eat it but they are discharged without being digested.