Kombu Day (Konbu no Hi)
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What Is "Kombu Day" on November 15th?
November 15th is "Kombu Day," established in 1982 by the Japan Kombu Association. The date was chosen to coincide with Shichi-Go-San, with the hope that growing children would eat nutrient-rich kombu and grow up strong, while also developing a lifelong habit of eating it. Kombu is associated with the word "yorokobu" (to rejoice) and has long been a must-have for celebratory meals, as well as a key ingredient supporting the dashi-based culture of Japanese cuisine. This anniversary helps spread awareness of its value.
Basic Knowledge About Kombu and Its Varieties
Representative Types of Kombu
| Type | Main Production Area | Characteristics & Best Uses |
|---|---|---|
| Ma-kombu | Southern Hokkaido (around Hakodate) | Refined, clear dashi, great for soups |
| Rishiri kombu | Rishiri Island, Hokkaido | A high-grade kombu that yields clear, refined dashi |
| Rausu kombu | Rausu, Hokkaido (Shiretoko Peninsula) | A high-grade kombu with rich flavor and a pleasant aroma |
| Hidaka kombu | Hidaka region, Hokkaido | Firm texture, great for tsukudani (simmered preserves) and rolled kombu |
Nutritional Components of Kombu
Kombu contains dietary fiber (such as alginic acid and fucoidan), minerals, and glutamic acid, the source of its umami. It is also high in iodine, an important nutrient used to make thyroid hormones, though too much should be avoided. Making good use of umami from dashi helps create satisfying dishes even with lighter seasoning.
How to Make Dashi and Compare Methods
The Difference Between Cold-Brewing and Boiling
There are two basic ways to make kombu dashi: "cold-brewing," in which kombu is soaked in water to draw out its umami, and "simmering," in which kombu is heated from cold water and removed just before boiling. Cold-brewed dashi has a clean taste, while simmering is handy when you want dashi quickly. "Awase dashi," combining kombu and bonito flakes, is the basic stock of Japanese cooking.
The Difference From Instant Granular Dashi
Granular dashi is quick and convenient, but dashi made from kombu has an aroma and flavor all its own. There is no need to make everything from scratch every day—try it first on a relaxed weekend, or in dishes where kombu is the star, such as clear soup or yudofu.
Food Habits Worth Revisiting on Kombu Day
Beyond dashi, kombu appears on the table in many forms, such as tsukudani, kombu rolls, tororo kombu, and shio kombu. As a lucky food linked to "yorokobu" (to rejoice), it is also a staple of celebrations. On this Shichi-Go-San day, why not enjoy a kombu dish together as a family?
In Summary
"Kombu Day" on November 15th was established in 1982 by the Japan Kombu Association in connection with Shichi-Go-San. Get to know the characteristics of varieties like ma-kombu and Rishiri kombu, and enjoy kombu in dashi and other dishes.