Some 90% of the konbu caught in the waters off Japan is from Hokkaido. There are various varieties of konbu kelp, such as naga-konbu, ma-konbu, and hosome-konbu, as well as those with regional brand names such as Rishiri-konbu, Rausu-konbu (oni-konbu), and Mitsuishi-konbu.
Capitalizing on its rich flavor, konbu kelp is used in soup broths, konbu-maki, oden and other simmered dishes, and tororo-konbu, which is minced kelp.
In recent years, the health and beauty effects of the calcium, iodine, and fiber contained in konbu kelp have been reaffirmed, increasing its popularity.
■Konbu kelp is harvested from nearly every coastline in Hokkaido
Hakodate is a major producer of ma-konbu, considered a luxury ingredient. In the Oshima region including Hakodate, fishermen use a hallow cage with a net pattern to catch the local specialty known as gagome-konbu because of its sticky texture. Each region also harvests kelp with a local name, such as naga-konbu and atsuba-konbu in the Nemuro area and Hidaka, Rausu and Rishiri konbu in each of these respective areas.
Hosome-konbu has the longest harvest history of any other konbu kelp in Hokkaido. It is caught only in small quantities along the Sea of Japan coast.
■ Map / Main municipalities with konbu grounds
Hakodate City, Shikabe Town, Fukushima Town, Shiriuchi Town
Wakkanai City, Rishiri Town, Rishiri Fuji Town, Rebun Town
Erimo Town, Samani Town, Urakawa Town, Shinhidaka Town
・Naga-konbu and Gaggara-konbu
Nemuro City, Hamanaka Town, Akkeshi Town, Kushiro Town, Kushiro City
Hokkaido’s ocean temperatures range between 5 and 20 degrees Celsius, ideal for growing konbu kelp year round. Hokkaido-grown kelp also thrives in the sunlight at depths between 5 and 7 meters. In addition to excellent natural conditions, the coastline offers rich minerals because of its currents, sea ice, or mountain waters flowing from mountain to sea.
The use of konbu kelp differs based on the variety, which enables products made in Hokkaido to be shipped based on the needs of each region in Japan. Konbu kelp was also an important item of trade carried on kitamaebune ships long ago.
Konbu harvesting mainly involves wrapping it around a scythe-like tool. Harvested konbu kelp is dried in the sunlight in a depot managed by each fisherman.
Konbu is mainly harvested in the summer and generally the harvest stops during the winter. As for Mitsuishi-konbu, after it is harvested in the summer, fishermen gather by hand the konbu that has been uprooted and is floating in the sea. Such harvesting takes place throughout the year.