“Hamanatto” is a fermented soybean product made with koji mold and aged for over a year. With a little creativity, there are many ways to enjoy this unique fermented soybean product…

“Hamanatto” is a fermented soybean product made with koji mold and aged for over a year.

Although it has “natto” in its name, it is actually closer to miso.

It is highly antioxidant—about 1.7 times more than regular stringy natto and roughly 20 times more than firm tofu.

Hamanatto is said to have antioxidant effects, such as helping to neutralize harmful free radicals and supporting the immune system.

Hamanatto can be enjoyed on its own or used as a seasoning.

With a little creativity, there are many ways to enjoy this unique fermented soybean product.

The 7-Generation History of Yamaya Soy Sauce

Founded in 1850 Yamaya Soy Sauce has a long 174-year history.

The company produces and sells traditional foods such as Hamanatto, as well as miso and soy sauce.

The current president, Mr. Toshimasa Kinpara, became the 7th-generation head of the company 27 years ago at the age of 20.

While still a university student, he faced the sudden passing of his father, the 6th-generation president, and made the firm decision not to let the historic Yamaya Soy Sauce company fail.

He spent his weekdays studying in Nagoya and his weekends helping with the family business in Hamamatsu.

With the support of his family, he successfully balanced both university and the family business during this challenging time, and continues to uphold the Yamaya Soy Sauce legacy as the 7th-generation president.

We Asked the 7th-Generation President About the Origins of Hamanatto

Hamanatto is said to have originated from touchi, a Chinese fermented soybean seasoning introduced to Japan along with the arrival of Buddhism.

Hamanatto has a strong connection with temples, and it is said that Hamamatsu’s Daifukuji Nattō, Kyoto’s Ikkyu-ji Nattō, and Daitoku-ji Nattō all share the same roots.

Hamanatto was also known as “shiokara nattō” or “tera nattō” (temple nattō).

According to legend, during the Sengoku period, Tokugawa Ieyasu, who was at Hamamatsu Castle, was so fond of the shiokara nattō presented from Daifuku-ji Temple that he repeatedly asked his retainers, “Has the Hamana nattō arrived yet?” Over time, the name evolved from “Hamana nattō” to “Hamanatto.”

In that sense, one could say that Tokugawa Ieyasu was the one who gave Hamanatto its name—a true masterpiece with a historic touch.

Yamaya Soy Sauce’s Commitment to Traditional Production

Yamaya Soy Sauce preserves traditional methods and produces Hamanatto completely additive-free.

Yamaya avoids shortcuts such as raising the warehouse temperature to shorten the aging process or using industrial fans to dry the beans. Instead, they rely on natural fermentation that slowly develops with the changing seasons and use the power of the sun to bring out the flavor.

This careful, traditional method preserves centuries-old wisdom in every batch.

Aged 15 Months: Yamaya Soy Sauce’s Hamanatto

To make Hamanatto, large black soybeans from Hokkaido are steamed and coated with koji mold, then mixed with saltwater and placed in containers.

About 100 kilograms of weight are placed on top to allow the beans to slowly ferment and mature over time.

After aging for 15 months, with additional saltwater added during the process, the beans are carefully removed from the containers, separated by hand, and then sun-dried.

Finally, shredded ginger is mixed in, completing the creation of Hamanatto.

Amazing! The Antioxidant Power of Hamanatto

Favored even by Tokugawa Ieyasu, Hamanatto is rich in antioxidants and is gaining attention as a health food.

According to 7th-generation president Mr. Toshimasa Kinpara, the soybean isoflavones in Hamanatto have about 1.7 times the antioxidant power of regular stringy natto and roughly 20 times that of firm tofu.

Thanks to its high antioxidant content and the power of fermentation, Hamanatto helps support the immune system, making it a truly healthful food!

Hamanatto: A Versatile Seasoning Packed with Umami

Hamanatto is rich in glutamic acid, a key component that gives it its savory umami flavor.

Hamanatto contains about three to four times more glutamic acid than regular miso.

Using it as a secret ingredient or flavor accent can add depth and richness to your dishes.

Kizami Hamanatto, finely chopped Hamanatto, is secretly used even in professional kitchens, including Michelin-starred restaurants.

This additive-free seasoning boosts umami and adds depth to a variety of dishes.

The wife of the 7th-generation owner has also shared recipes using Hamanatto—definitely worth checking out for inspiration!

Yamaya Soy Sauce Kitchen: https://cookpad.com/jp/users/40113454

Where to Buy Yamaya Soy Sauce’s Hamanatto

In Hamamatsu, you can find Hamanatto at the following locations:

Kiosk Gift Station inside JR Hamamatsu Station

Hamamatsu Matsuri Museum (Nakatajima, Hamamatsu-shi) souvenir shop

Hamamatsu Castle Hamamatsu Brand Corner

Okura Act City Hotel Hamamatsu

Shin-Tomei Hamamatsu SA (both directions)

Entetsu Department Store, Basement 1F

Denkuu Shunsai Market

Yataro Outlet Store, factory direct shop

Café Oliva

Lupinus no Hata

You can also purchase Hamanatto from the official Yamaya Soy Sauce online shop.

Be sure to check it out!

*Please note that availability may change.

7th-Generation’s Recommendation! “Fermented Umami Oil” Made with Kizami Hamanatto

The Fermented Umami Oil, made with finely chopped Hamanatto, won the top award out of 1,019 entries at the Food Action Nippon Award 2020.

This popular product has a reputation for turning any dish into a professional-level meal—just drizzle or spread it!

Completely additive-free, it’s loved by a wide range of people as a healthy, versatile seasoning.

A Message from Mr. Toshiyuki Kinpara, 7th-Generation Owner

I continue the production of Hamamatsu’s “hidden specialty,” Hamanatto, following in the footsteps of my late father.

With the resolve to make the Hamanatto I inherited from my father more widely known before the day I retire, I have spent the past 27 years taking on various challenges.

Determined to move beyond the image of Hamanatto as a product only for the elderly or enthusiasts, I explored its potential as a versatile seasoning.

As a result, it has been featured in numerous media outlets, and I’ve even had the opportunity to appear on programs alongside celebrities usually seen only on TV.

There was also a memorable moment when professional chefs told us that they had used a recipe my wife, who is not a professional cook, created on Cookpad as a reference for developing their own menus—a truly encouraging experience.

If I may say so myself, the deliciousness of Hamanatto when used as a seasoning exceeded even my own expectations.

After experimenting nightly, using Hamanatto with a variety of dishes as my drinking companion, I discovered that combining it with olive oil created something special.

This led to the development and release of the Fermented Umami Oil, which was highly acclaimed and even received the top award from Amazon Japan out of 1,019 entries.

Although I felt the product had potential from the very beginning, I never imagined it would receive such high praise from Amazon Japan.

I truly believe that the deliciousness of Hamanatto, a traditional fermented food free of additives and preservatives, still holds great potential.

Moving forward, I will continue striving to provide healthy and tasty products that bring joy to everyone.

Please look forward to what’s next!

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This time, we introduced Yamaya Shoyu.

Why not try incorporating their additive-free Hamanatto, made using traditional methods, into your daily meals? 🍚

Official Website: https://ymy.co.jp/

Instagram: https://www.instagram.com/yamaya.hamanatto_official/

Photo credit: Yamaya Shoyu