PRODUCER SPOTLIGHT: Farming Japanese "Phantom Soybeans" - Exclusive Interview with Toyokuniya

  • 4 min read

Toyokuniya, located in Sagamihara City in Kanagawa Prefecture, is a family-run farm that cultivates an heirloom variety of Japanese soybeans called “Tsukui soybean” - a once common soybean variety that has become so rare in Japan that it’s now called the “phantom soybean.”

Sadly there are very few domestic soybean producers left in Japan. Japanese farmers have been unable to compete with foreign-grown soybeans and now almost 90% are imported. Toyokuniya is one of the few remaining Japanese soy farmers who continue to harvest soybeans using their own hands while producing and seeding offspring to support continued growth in the future.

Masahiro and Kayoko Okamoto, the couple behind Toyokuniya, have three children and were always looking for creative and delicious foods to feed them. Using this inspiration, Toyokuniya creates natural and unique, pesticide-free products including soy dressings, soy sauce, miso, steamed soybean snacks, soy coffee, sweet soybean treats and a wide-range of fermented products.

Their daughter, Fukiko Okamoto,who sells custom-made, body- and mind-friendly sweets at Toyokuniya, sat down with her dad to share his journey as an heirloom soybean farmer. 

Toyokuniya Soybean Farmer Masahiro Okamoto


Fukiko: You have a liquor store and produce soybeans. What do soybeans have in common with liquor?

Masahiro: I got into the liquor business when I met my wife and decided to help at her parents’ liquor store. Before that, I was helping in my family’s fishing business in Enoshima in Shonan, where I was born and raised.

I became interested in food, especially organic Japanese food, once I had a family and my children were getting older. I was particularly fascinated by Japanese soybeans, which are an indispensable ingredient in Japanese foods like soy sauce, miso, and tofu. I discovered a variety of soybeans called “Tsukui zairai daizu” (meaning Tsukui conventional soybeans), which had been handed down from generation to generation in the local area. The flavor of the soybeans shocked me. I was amazed by how delicious the soybeans were and I knew that I definitely wanted to make these soybeans into products to sell.

Japanese soybeans


Fukiko: How do you come up with the unique product ideas for Toyokuniya? What aspects of the products are you particular focused on?

Masahiro: Most come as flashes of insight! But to get that inspiration, I always keep my ear to the ground by reading news about agriculture and economics. Also when customers come to our store and sample our products, we ask for their opinions. After all, the most important thing is that people eat our products and think, “Wow this is delicious!”. When creating products, I want to make the most of the natural deliciousness of the tsukui zairai daizu soybeans. As a result, we try to make our products as simple as possible. We do not use any harmful additives or chemical substances.

Fukiko: How did you first create “natto koji”? How do you recommend using it?

Masahiro: Actually, products similar to natto koji have long been produced in the Tohoku region of Japan, although they are not common in Tokyo. The concept of natto koji is to ferment the already fermented natto with koji - double fermentation! The result is an unbelievable food that allows you to enjoy the wonderfulness of fermentation twice. In addition, the double fermentation process takes away the stinky and sticky nature of natto making it very easy to eat even for natto skeptics. We packaged the natto koji in a tube to make it easy to use, even for elderly people and small children. I recommend mixing the natto koji with sesame oil and bonito flakes for a snack. You can also try mixing the natto koji with a little olive oil and use it as a spread on toasted bread.

Toyokuniya Soybean Farmer Masahiro Okamoto

Fukiko: What are the challenges of our modern food system? What are you hoping to accomplish through Toyokuniya?

Masahiro: For one, although people in Japan eat soy sauce, miso, and natto, which are all made from soybeans, the soybean self-sufficiency rate in Japan is only 5%. Most companies making soybean products rely on imported soybeans. If Japan does not start producing more of its own produce, including soybeans, we will face food shortages. You can make 100 soybeans from just one soybean. As a start, why not planting and growing soybeans yourself? At Toyokuniya we organize a variety of hands-on workshops from soybean planting and harvesting, to miso-making classes with elementary and junior high school students. As much as possible, I want to continue holding food education programs.

Toyokuniya Japanese Soybean Farm

Fukiko: What is your message to customers outside Japan?

Masahiro: “Food” is a product of the physical land, local environment, and long history of the place where it is cultivated. As a result, “Japanese food” is food that developed to suit people in Japan. However, recently, Japanese food and fermented foods have gained popularity around the globe as healthy foods. “Hakkou” in Japanese means “fermentation,” which means to boil over, to burst, to overflow, to be excited. In other words, the creation of life itself is “hakkou”.

Fukiko Okamoto was born in Kanagawa prefecture. After graduating from a confectionery vocational school, she worked at several cake stores. She became interested in natural food and and infant care, and worked at a nursery school for natural childcare for 6 years. She moved to San Diego, California, where he started Fuki Cakes, which sells custom-made, body- and mind-friendly sweets made mainly from organic ingredients without the use of white sugar or additives. After her short-term study abroad program, she returned to Japan in 2020 where she now sells cake boxes and custom-made sweets once a month at her parent's farm, Toyokunya.

Read more about Okamoto's family farm and their unique soy products in our Producer Spotlight.

Learn more about Toyokuniya at

2 Responses

Kokoro Care Packages

Kokoro Care Packages

March 05, 2022

Thank you for your interest in this special product! We’ll let you know as soon as it becomes available (should be shortly as we wait for the next batch)

Ginger Bertero

Ginger Bertero

March 05, 2022

Put me on the list to purchase natto when it come available.

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