Saccharina japonica is a marine species of the Phaeophyceae (brown algae) plant, a type of kelp or seaweed, which is extensively cultivated on ropes between the seas of China, Japan and Korea. It is widely eaten in East Asia. A commercially important species, S. japonica is also called ma-konbu (真昆布) in Japanese, dasima (다시마) in Korean and hǎidài (海带) in Chinese. Large harvests are produced by rope cultivation which is a simple method of growing seaweeds by attaching them to floating ropes in the ocean. Consuming excessive S. japonica suppresses thyroid function.