Saccharina japonica

Saccharina japonica is a brown alga, a type of kelp, commonly known as sweet kelp. It is widely farmed using rope cultivation—a straightforward technique where the seaweed is attached to floating ropes in the ocean—primarily in the seas around China, Japan, and Korea. This species is a major food item in East Asia and goes by the names ma-konbu in Japanese, dasima in Korean, and hǎidài in Chinese. Beyond Asia, it is also cultivated in Russia and France. In China and Japan, it is one of the two most commonly consumed kelps. China alone produces up to ten thousand tons of alginates from this seaweed each year.

The kelp contains very high levels of iodine. Eating 15 grams per day—which provides 35 milligrams of iodine—can suppress thyroid function, though thyroid hormone levels usually stay within normal ranges.

In terms of classification, the species was moved to the genus Saccharina in 2006. Its older names include Laminaria japonica, Laminaria japonica var. ochotensis, and Laminaria ochotensis. A 2026 study suggested that Saccharina diabolicha and Saccharina religiosa are the same species.

Most Japanese kombu—over 90%—is grown in Hokkaidō. Thanks to advances in farming, it is now produced as far south as the Seto Inland Sea.

In Chinese cooking, sliced kelp is a common appetizer, often eaten with alcohol. In Korean cuisine, dasima is used to make broth, deep-fried as bugak or twigak, pickled in soy sauce as jangajji, or eaten raw as a wrap. It is also brewed into dasima-cha (kelp tea). Cheonsa-chae, or kelp noodles, are made from the alginic acid in dasima. Nongshim’s Korean version of Neoguri instant noodles includes one large piece of dasima per package, and Ottogi’s Odongtong Myon has contained two pieces since 2020.