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Naturally Freeze-Dried! Japanese Traditional "Frozen Tofu"

Updated: Apr 26, 2022

Introducing noteworthy nutritional values and unique recipes!

Tofu has become so popular as a staple of healthy food, but have you ever heard of "Kori-Tofu," or frozen and dried tofu? Kori-Tofu is a traditional Japanese preserved food that has been eaten since olden times in the cold mountainous areas of the Tohoku region and Nagano Prefecture. Many people may be surprised at the idea of frozen tofu. If you have never tasted it before, you may be curious about what it tastes like. In this article, we will introduce the origins of Kori-Tofu prepared in the middle of winter, where it came from, how it is made, and some nutritional information and unique recipes. Table of Contents 1. Two origins of Kori-Tofu 2. The nutrients in Kori-Tofu 3. Recipes using store-bought Kori-Tofu 4. Recipes using homemade Kori-Tofu 5. Summary

1. Two origins of Kori-Tofu

↑ Koya Mountain in snow. In this cold weather, "Koya Tofu" was born. As the name suggests, "Kori(=Frozen in Japanese)-Tofu" is made by freezing tofu. There are two lineages of Kori-Tofu that can be traced back to its origins. The first is "Koya Tofu," which originated in Koya-san (Mt. Koya), a holy place of Japanese Buddhism in Wakayama Prefecture. The other is "Shimi(=Frozen in Japanese also)-Tofu," which originated in the cold rural areas of Shinshu and the Tohoku region. Although there are differences in the names of the different regions, the unified name "Kori-Tofu" is defined by the Japanese Agricultural Standards (JIS). We use "Kori-Tofu" as a proper term. There are many stories about the origin of frozen tofu, but for "Koya Tofu," the birthplace is believed to be Koya-san monastery, located in Koya-cho, northern Wakayama Prefecture. Koya-san monastery is a sacred place of Buddhism in Japan, founded by the famous Buddhist monk Kobo-Daishi Kukai, and was registered as a World Heritage Site in 2016. The story goes that a young monk at a temple in Koya-san inadvertently left tofu outdoors on a cold winter night, and when he ate the frozen tofu the next day, it was delicious. Legend has it that Kukai brought tofu-making techniques back to Japan from China, where he studied soybeans. It is said that when the monks who practiced Buddhism at Koya-san spread the teachings of Buddhism throughout Japan, Koya Tofu, a preserved food that is lightweight, easy to carry around, and highly nutritious, also spread throughout the country.

↑ Vegetarian food served at Koya-san monastery. The bowl in the center of the foreground contains simmered Koya-Tofu. (Both photos courtesy of Wakayama Tourism Federation) On the other hand, "Shimi-Tofu"(Shimi also means frozen in Japanese) is said to have been first produced around the Momoyama period (1573-1603) in frigid regions where the temperature drops below zero in winter. The tofu is made by repeatedly freezing and drying in sunlight by weaving slices of firm tofu with straw and hanging them outside in the winter. In Nagano Prefecture, surrounded by the Japanese Alps and other mountains, Shimi-Tofu became popular as a winter side job for farmers and became a production area. Today, Nagano Prefecture is a significant producer of Kori-Tofu, accounting for 98% of the total production in Japan. However, because mass production is now possible using the "artificial freezing" method, which is not affected by weather conditions, only a few people produce frozen tofu traditionally.

↑Shimi-Tofu is made by slicing hard, firm tofu.

↑ They hang the tofu under the eaves during the cold season when the temperature drops below zero to freeze and dry repeatedly.