Natto Soup | A Comprehensive Explanation of the History, Preparation Method, and Nutritional Value of Yamagata Prefecture’s Representative Winter Local Dish
Natto soup (nattou jiru) is a winter local dish that has been cherished since ancient times, particularly in the inland areas of Yamagata Prefecture. This dish, created by thoroughly mashing natto in a mortar until the individual beans are no longer visible and then adding it to miso soup to produce a unique thickness and flavor, has become an indispensable part of Yamagata’s winter dining tables.
The cooking method of “adding natto to hot soup,” which is rare nationwide, may seem like a mismatch at first glance. However, this dish, which warms the body from its core and boasts excellent nutritional value, embodies the traditional wisdom specific to snowy regions.
Natto Soup | A Winter Local Dish Representing Yamagata Prefecture
Natto soup is a miso-based soup dish that has been cherished in Yamagata Prefecture since ancient times. Its most distinctive feature is the unique thickness created by carefully mashing natto in a mortar or food processor until it becomes sticky and dissolving it into the soup.
This thickness clings well to the ingredients and enhances the heat-retention effect, warming the body from its core during the cold winter months. The ingredients include tofu, fried tofu, mushrooms, wild vegetables, and root vegetables. In particular, “imogara,” the dried stems of taro plants (also called zuiki), is known as a traditional ingredient indispensable to natto soup.
Main Areas of Transmission
Natto soup is cherished throughout a wide range of the Tohoku region, but it is particularly popular in the inland areas of Yamagata Prefecture (Yamagata City, Shinjo City, Tendo City, etc.). It is also transmitted as a local dish in Akita Prefecture (Yuzawa City, etc.) and Iwate Prefecture (Nishi-Waga Town, etc.), with each region developing its own unique ingredients and cooking methods.
Even within Yamagata Prefecture, there are variations in ingredients and seasonings depending on the region and household, with each family’s own taste being passed down. The dish is also eaten in the Shonai region (Sakata City, Tsuruoka City), and can be said to be loved throughout all of Yamagata Prefecture.
History and Origins of Natto Soup | Winter’s Nutritional Source Born from Snowy Region Wisdom
Natto soup has a long history, born in the inland regions of Yamagata Prefecture as wisdom for surviving the harsh winters. In the past, inland regions such as Yamagata had limited opportunities to consume fresh vegetables and animal protein during the winter months.
Thus, by combining preserved natto, miso, tofu, and fried tofu—soybean products with good shelf life—and adding wild vegetables (imogara, bracken, warabi, etc.) and mushrooms that had been harvested in autumn and dried for storage, people created a valuable source of protein and vitamins during the winter months.
Occasions and Seasons for Eating
Natto soup is primarily eaten during winter, particularly between November and March. In Yamagata Prefecture, the custom of eating natto soup on January 7th, the day of “Nanakusa” (Seven Herbs), remains strong in many areas. While the custom of eating seven-herb rice porridge on this day is known nationwide, in Yamagata many households eat natto soup to pray for good health and freedom from disease.
Additionally, during the cold year-end and New Year periods and the depths of winter when snow accumulates heavily, it has been frequently made in households for dinner. Today, it remains popular as soul food for Yamagata residents, enjoyed at dinner on cold days or when the body feels chilled.
Nutritional Value of Natto Soup | Soybean Power Concentrated in One Bowl
The most distinctive feature of natto soup is that multiple soybean products are used in a single dish. Since four soybean-based products—natto, miso, tofu, and fried tofu—can be consumed at once, it is abundant in high-quality plant-based protein.
Main Nutritional Components and Health Benefits
Natto, as a fermented food, possesses excellent nutritional value, and an enzyme called nattokinase is said to provide a blood-thinning effect. It is also rich in vitamin K2, B vitamins, and dietary fiber.
Miso, also as a fermented food, contains enzymes and lactic acid bacteria that aid digestion and absorption, with expected benefits for intestinal health.
Tofu and fried tofu provide high-quality protein and calcium, and fried tofu in particular contains moderate amounts of fat, making it useful for energy replenishment.
Furthermore, imogara, used as an ingredient, is rich in dietary fiber, mushrooms provide vitamin D and minerals, and wild vegetables supplement vitamins and minerals. Garnish vegetables such as green onions and water parsley are said to have body-warming effects, making them a nutritionally sound combination for winter cold countermeasures.
In this way, natto soup is a dish rich in nutritional balance, embodying the wisdom for spending a healthy snowy winter.
Main Ingredients Used in Natto Soup
The ingredients used in natto soup vary by region and household, but the basic materials are as follows:
Essential Ingredients
- Natto: The main ingredient, characterized by mashing until individual beans are no longer visible
- Miso: Rice miso or barley miso from Yamagata Prefecture is often used
- Tofu: Either firm tofu or silken tofu
- Fried tofu: Oil-blanched and cut into thin strips
- Broth: Dried anchovy broth, kelp broth, or a combination thereof
Standard Ingredients
- Imogara (taro stems): Dried stems of taro plants, a representative ingredient in natto soup
- Konnyaku: Used cut into thin strips or torn by hand
- Mushrooms: Nameko, shimeji, maitake, etc. Naturally gathered mushrooms from autumn, dried for storage, are sometimes used
- Root vegetables: Daikon radish, carrot, burdock, etc.
- Wild vegetables: Canned or dried bracken, warabi, butterbur, and similar plants
- Green onions: Long green onions sliced diagonally
- Water parsley: Added last as a flavorful garnish
Variations by Region and Household
Ingredient variations are abundant depending on the household and region. Some households add potatoes, taro, thick fried tofu, shirataki noodles, or chicken. Additionally, the more vegetables added, the more delicious it is said to become, and it is common practice to freely add whatever vegetables are in the refrigerator.
How to Make Natto Soup | Detailed Explanation of an Authentic Recipe
The keys to making delicious natto soup are carefully mashing the natto and avoiding overcooking the ingredients. Here, we explain the traditional preparation method in detail using a recipe for 5 servings.
Ingredients (5 servings)
- Natto: 2 packages (approximately 100g)
- Firm tofu: 1 block (300g)
- Fried tofu: 2 sheets
- Imogara (dried): 20g
- Konnyaku: 1/2 sheet
- Nameko mushrooms: 1 package (100g)
- Daikon radish: 100g
- Carrot: 50g
- Burdock: 50g
- Long green onion: 1 stalk
- Water parsley: 1 bunch (50g)
- Broth: 1200ml
- Miso: 4-5 tablespoons (adjust to taste)
- Seven-spice chili powder: as needed
Preparation
- Imogara is rehydrated in water (approximately 30 minutes) and cut into bite-sized lengths (3-4cm)
- Fried tofu is blanched with hot water to remove excess oil and cut into thin strips
- Tofu is cut into cubes
- Konnyaku is torn by hand or scooped out with a spoon into bite-sized pieces
- Daikon radish and carrot are cut into ginkgo leaf shapes, burdock is shaved thinly and soaked in water
- Green onion is sliced diagonally, water parsley is cut into 3-4cm lengths
- Nameko mushrooms are rinsed lightly
Preparation Steps
1. Mash the Natto
This is the most important step in making natto soup. Place natto in a mortar and mash thoroughly with a pestle until the grains are completely invisible. The more you mash, the more sticky it becomes, resulting in a smooth paste. This process takes approximately 5-10 minutes of thorough mashing.
If you don’t have a mortar, you can use a food processor or blender, but the traditional method uses a mortar. Adding small amounts of water while mashing will result in a smoother consistency.
2. Cook the Ingredients in Broth
Pour broth into a pot and heat, adding the harder-to-cook ingredients in order. First, add daikon radish, carrot, burdock, imogara, and konnyaku and simmer over medium heat. Cook until the vegetables are tender, approximately 10 minutes.
3. Add Tofu and Fried Tofu
Once the root vegetables are tender, add the tofu and fried tofu. Handle the tofu gently as it breaks apart easily when cooked. Simmer for another 3-4 minutes.
4. Add the Mushrooms
Add mushrooms such as nameko. Since mushrooms lose their flavor when overcooked, cooking for 2-3 minutes is sufficient.
5. Dissolve in the Miso
Lower the heat and dissolve in the miso. Since the flavor of miso is lost if boiled, be careful not to bring to a boil after dissolving it in.
6. Add the Mashed Natto
Thin the mashed natto with a small amount of broth before adding it to the pot. After adding the natto, stir well to blend it throughout. At this point, the natto’s thickness spreads throughout the soup, creating a unique texture.
7. Finishing Touches
Finally, add the green onion and water parsley, and bring to a simmer, then remove from heat. The key point is to add the water parsley and remove from heat immediately so as to enjoy its fragrance.
Serve in bowls and top with seven-spice chili powder to taste.
Tips and Points for Preparation
- Mash the natto thoroughly: If grains remain, the texture will be poor, so it is important to take time to mash until smooth
- Don’t overcook the ingredients: Especially tofu and mushrooms should be cooked for an appropriate length of time to prevent them from falling apart or losing their flavor
- Don’t boil the miso: Avoid boiling to preserve the flavor and nutrition of the miso
- Add the natto last: If natto is added too early, its flavor will dissipate, so add it at the finishing stage
- Add water parsley last to preserve its fragrance: To enjoy the fresh fragrance of water parsley, add it just before removing from heat
How to Enjoy and Serve Natto Soup
Natto soup is typically eaten hot with rice. In Yamagata Prefecture, a simple winter meal consisting of natto soup as the main dish, with rice and pickles on the side, is standard.
Eating Variations
Over rice: A popular way to enjoy natto soup is to pour it over rice, creating a rice-soup dish. The thick soup clings well to the rice and warms the body.
With udon noodles: Another way to enjoy natto soup is to use it as a noodle broth for udon. It becomes a nutritious dish full of ingredients.
Next-day arrangements: Natto soup left overnight develops a more blended flavor and tastes even better. Reheat with a little additional water.
Garnishes and Seasonings
In addition to seven-spice chili powder, you can add Japanese pepper, shiso leaves, or yuzu pepper to create variations in flavor. Some households also add a small amount of butter at the end for increased richness and a more Western flavor.
Conservation and Transmission Efforts of Natto Soup
Natto soup is being preserved and transmitted in various forms as an important aspect of Yamagata Prefecture’s food culture.
School Lunch Service
Many elementary and middle schools in Yamagata Prefecture include natto soup in school lunches as part of food education to learn about local dishes. This provides children with a valuable opportunity to learn the region’s traditional flavors and plays a significant role in transmission to the next generation.
Cooking Classes and Events
Local cooking classes hosted by community centers and living improvement groups teach how to make natto soup. It is particularly popular as an opportunity to experience the traditional technique of mashing natto in a mortar.
Additionally, natto soup is served at many food events and festivals in Yamagata Prefecture, providing visitors from outside the prefecture with an opportunity to experience Yamagata’s flavors.
Commercialization and Modern Initiatives
In recent years, efforts have progressed to make natto soup more readily accessible through freeze-dried and retort packet products. These are sold by food manufacturers and roadside stations in Yamagata Prefecture, making it possible for people outside the prefecture to enjoy Yamagata’s flavors at home.
Information dissemination through social media is also active, with younger generations posting natto soup arrangement recipes and publishing cooking videos, advancing transmission in new forms. Natto soup-related products are also sold at Yamagata Prefecture antenna shops, increasing awareness in metropolitan areas such as Tokyo.
Registration in the Ministry of Agriculture, Forestry and Fisheries “Our Local Cuisine” Database
Natto soup is also registered in the “Our Local Cuisine” database operated by the Ministry of Agriculture, Forestry and Fisheries, introduced nationally as a representative local dish of Yamagata Prefecture. This officially recognizes its value as Japanese culinary cultural heritage and raises awareness of the importance of its preservation and transmission.
Connection to Other Yamagata Prefecture Local Dishes
Natto soup, as part of Yamagata Prefecture’s rich food culture, colors the regional dining table alongside other local dishes.
Imo-ni is a fall representative local dish of Yamagata Prefecture, made by simmering taro and beef in a soy sauce broth. In contrast to imo-ni, which is associated with the fall excursion season, natto soup is a winter home-cooking dish.
Dashi is a cold garnish made by finely chopping summer vegetables, a dish that stimulates appetite during hot summers. The existence of different local dishes by season illustrates the richness of Yamagata Prefecture’s food culture.
Hippari udon is a local dish from the inland areas of Yamagata Prefecture eaten with natto and raw egg as broth, sharing the use of natto with natto soup. It exemplifies the Yamagata residents’ love of natto.
These local dishes are each deeply connected to Yamagata Prefecture’s climate, history, and living habits, forming important elements of the region’s identity.
Places Where You Can Taste Natto Soup
Since natto soup is cherished as a home-cooked dish, there are limited establishments that serve it, but you can taste it in the following places.
Local Cuisine Restaurants
Restaurants in Yamagata City and throughout the prefecture that serve local cuisine sometimes offer natto soup as a winter-season special menu item. Restaurants that particularly emphasize local ingredients can serve authentic natto soup that respects traditional preparation methods.
Roadside Stations and Tourist Facilities
Dining areas at roadside stations and tourist facilities throughout Yamagata Prefecture sometimes serve natto soup as a local dish. It is particularly popular in winter as a warming local cuisine for tourists.
Farm Restaurants and Farm Inns
Restaurants and inns operated by farmers sometimes serve authentic natto soup made with local ingredients. In particular, natto soup made with homemade miso and locally grown vegetables has an exceptional flavor.
Events and Festivals
Natto soup is sometimes served at food events and community festivals held during winter. Natto soup enjoyed by a large group serves to deepen the bonds of the local community.
Conclusion | A Local Flavor Supporting Yamagata’s Winter
Natto soup is a local dish embodying the wisdom of ancestors in surviving Yamagata’s harsh winters. The unique thickness produced by mashed natto and the high nutritional value of being able to consume multiple soybean products—tofu, fried tofu, and miso—all at once are characteristics unmatched by others.
By utilizing ingredients such as imogara, wild vegetables, and mushrooms that were harvested in autumn and preserved for storage, it has served as a valuable source of vitamins and minerals during winter. The heat-retention effect that warms the body from its core and its excellent nutritional balance represent the crystallization of food wisdom specific to snowy regions.
In modern times, transmission activities to the next generation are being actively carried out through school lunches, cooking classes, and product commercialization. While maintaining tradition, transmission is also progressing through new forms such as information dissemination via social media and the development of new arrangement recipes suited to the times.
When visiting Yamagata Prefecture, be sure to taste authentic natto soup. It is also relatively easy to prepare at home, so trying the traditional method of mashing natto in a mortar is also worthwhile. Once you taste it, you will understand why Yamagata residents have cherished it for so many years through its warmth and gentle flavor.
Natto soup goes beyond being merely a dish to become a symbol of Yamagata’s winter life and culture. We hope that this precious food culture will continue to be passed down to future generations.
