Nori is a thin, dried sheet of edible red seaweed (species in the genus Pyropia, formerly classified as Porphyra), most familiar as the wrapper for sushi rolls. It has been eaten in Japan since at least the 8th century, though the sheet form used today wasn't developed until nori farming and paper-making-style drying techniques emerged during the Edo period (17th-18th century). Beyond sushi, nori is toasted and crumbled as a seasoning over rice, soups, and salads, or eaten on its own as a salty, umami-rich snack. Japan remains the main producer, particularly the Ariake Sea and Seto Inland Sea, with significant cultivation also in China and Korea, where it is used in dishes like gimbap and hot pot.