Tsuku Shin, 10 Year Aged Ma Kombu, Shiroikuchihama, Grade 1, 500g
Decade-Aged Wild Kombu from Hakodate's Most Prestigious Shore
Ma kombu (真昆布) is the highest-grade kelp in Japanese cuisine — the foundation of refined dashi stock and the benchmark against which all other kombu is measured. Tsuku Shin's 10 Year Aged Shiroikuchihama Ma Kombu (白口浜天然真昆布 10年熟成) is as good as it gets: wild-harvested from Shiroikuchihama in Hakodate — one of three elite kombu-producing shores in Hokkaido — graded 1等検 (Grade 1 Inspected), then aged for a full decade in controlled storage. That ageing process does what time does to fine wine: it rounds off the raw marine edge, deepens the umami, and produces a dashi of extraordinary clarity and refinement. This is the kombu that Kyoto's top kaiseki kitchens build their cuisine around.
Why Chefs Choose This
- Shiroikuchihama origin: One of the three named shores in Hakodate's elite kombu district. Shiroikuchihama ma kombu is prized for producing the clearest, most elegant dashi — the preferred kombu of Kyoto's kaiseki tradition.
- 10 year ageing: A decade of controlled storage reduces moisture, concentrates glutamic acid (umami), and mellows the raw seaweed character. Aged kombu produces a noticeably smoother, more refined stock than fresh-season kombu.
- Grade 1 Inspected: 1等検 — the top classification under Japan's kombu grading system, based on thickness, colour, width, and absence of defects.
- Wild-harvested (天然): Not farmed. Wild ma kombu develops in the natural tidal currents of the Tsugaru Strait, producing a denser, more flavourful leaf than cultivated alternatives.
How to Use
- Ichiban dashi (first stock): Cold-soak a 10cm piece in 1L water for 30–60 minutes, then heat slowly to just below boiling and remove. The result is a clear, golden stock with deep umami and no cloudiness.
- Kaiseki-grade applications: Suimono (clear soup), chawanmushi (savoury custard), shabu-shabu broth — anywhere the dashi is the star, not the supporting act.
- Niban dashi (second stock): Re-simmer the used kombu with bonito flakes for a robust everyday stock — nothing wasted.
- Kombu-jime: Use a strip to cure sashimi-grade fish between two sheets of kombu for 2–4 hours. The ageing makes this kombu particularly effective for kombu-jime, as the concentrated glutamates transfer more readily.
Why does aged kombu make better dashi?
Fresh-season kombu produces good dashi, but it retains more moisture and a stronger raw marine character. Over a decade of controlled ageing, the moisture content drops, the glutamic acid (the amino acid responsible for umami) concentrates, and volatile compounds that create harsh or "seaweedy" notes gradually dissipate. The result is a stock that's cleaner on the palate, richer in umami, and more transparent in colour. It's the same principle as ageing cheese or dry-ageing beef — time removes what you don't want and concentrates what you do. In Kyoto's kaiseki tradition, aged ma kombu from Hakodate's named shores is considered essential, not optional.
Product Details
| Type | 真昆布 — Ma Kombu (True Kelp) |
| Producer | つく新 Tsuku Shin |
| Harvest Area | 白口浜 Shiroikuchihama, Hakodate, Hokkaido |
| Harvest Method | 天然 Tennen (Wild-Harvested) |
| Grade | 1等検 (Grade 1 Inspected) |
| Ageing | 10年熟成 (10 Year Aged) |
| Weight | 500g |
| Storage | Store in a cool, dry place away from direct sunlight. Reseal after opening. |
What is Shiroikuchihama kombu?
Shiroikuchihama (白口浜) is one of three named kombu-producing shores in the Hakodate region of southern Hokkaido, alongside Kurokuchihama and Motomachihama. These three shores have been recognised for centuries as producing Japan's finest ma kombu. Shiroikuchihama kombu is particularly valued for its ability to produce a clear, elegant dashi with refined umami and no cloudiness — the reason it became the preferred kombu of Kyoto's kaiseki cuisine, where visual clarity of the stock is as important as flavour.
What is the difference between wild and farmed kombu?
Wild kombu (天然 tennen) grows naturally on the seabed, anchored to rocks in tidal currents. It develops over two or more years, building density and flavour as it competes for nutrients and withstands ocean forces. Farmed kombu (養殖 yoshoku) is cultivated on ropes and typically harvested after one year. Wild kombu is thicker, denser, and richer in glutamic acid — it produces a more complex, layered dashi. The 天然 designation on this product confirms it is wild-harvested, not cultivated.
How is kombu graded in Japan?
Japanese kombu is graded by official inspectors based on thickness, width, colour, moisture content, and absence of damage or defects. Grade 1 (1等検) is the highest classification — it indicates kombu that meets the top standard across all criteria. Lower grades (2等, 3等, and below) are still usable but may be thinner, narrower, or have cosmetic imperfections. For dashi-focused applications where quality is paramount, Grade 1 is the professional standard.
SKU : K0187