【Reading】こうやどうふ

【English Name】Freeze-Dried Tofu

Tofu is exposed to cold, frozen, aged at low temperature, and then its moisture is removed—this is how koya-dofu (freeze-dried tofu), an ancient Japanese preserved food, is made. When the dried product is soaked in water it becomes porous and absorbs plenty of dashi umami. It has long been cherished as an indispensable ingredient in simmered dishes.

There are several accounts of its origin. On Mt. Koya, the monk Mokujiki Ogo is said to have perfected the production technique as a food for ascetic practice, and when it spread to various regions as a souvenir during the Edo period, the name "koya-dofu" took hold. In the Tohoku region, a similar preserved food called "shimi-dofu" has been handed down, with a legend that the warlord Date Masamune created it in the course of developing field provisions. Since similar products are also found in China, some point out that the food arose independently in cold climates.

Nutritionally, in its dried state, 100 g contains about 50 g of protein and about 630 mg of calcium, making it highly nutritious. Its high content of resistant protein has also drawn attention in recent years, and its effect of improving lipid metabolism is being verified academically. Nagano Prefecture accounts for more than 90% of domestic production. In its connection to sushi, a standard way of eating it is to simmer it in a sweet-savory broth and add it to chirashi sushi or rolled sushi.