Hidaka Konbu

Its formal name is mitsuishi kelp. Softer-fibered and faster-cooking than other kelps, it is sometimes called "quick-boiling kelp." The spent leaves are easy to turn into a simmered side or soy-simmered dish after making stock — an all-round usefulness said to be why households keep it on hand, aiming at a different goal from kelp bred purely for stock elsewhere.

Kelp cut at dawn is spread out on the beach and left to soak up a full day of sunlight. The gaps between the pebbles of the gravel beach are said to provide just enough airflow to aid drying, and this sun-drying method, largely unchanged for over a century, is said to produce a flavor unlike any other — patient, weather-dependent work with no shortcut through machinery.

Production was originally confined to the Mitsuishi area of what is now Shinhidaka, before spreading along the wider Hidaka coast as demand grew. Where other regions bred kelp purely for stock, hardened for that purpose, this one leaned into being soft and quick to cook — and so became the kelp that settled into everyday home cooking, its very usefulness driving the spread of production.