The secret to Nagano’s delicious miso production lies in its crystal clear water. The prefecture is blessed with abundant water resources, including plentiful snowmelt that gushes through the high mountains surrounding Nagano. Water plays an important role in every step of the miso-making process, including washing, soaking, and steaming of the soybeans and rice. The climate of Nagano, with its wide range of temperatures, also encourages the slow maturation and fermentation of miso. Miso is fermented by the action of koji (a fungus used to ferment food in Japan), yeast, and lactic acid bacteria. These bacteria produce many amino acids and vitamins from the high-quality protein in the soybeans, as well as minerals, carbohydrates, fats, and other nutrients, making miso a vegan, fermented food attracting attention from around the world.

Miso is generally an indispensable part of the Japanese diet, but Shinshu Miso first became known throughout Japan when Tokyo was devastated by the Great Kantō earthquake (1923). Nagano Prefecture, being geographically close to Tokyo whilst not being directly affected by the disaster, delivered Shinshu Miso as a relief supply. Although Shinshu Miso has become nationally famous in this way, every household in Nagano still has their own taste of home that they have grown up with, and these tastes have been cherished through the ages. Just as there are many different cheeses and meats from different regions in Italy’s mercato, there are many variations of Shinshu miso from region to region. Miso is an integral part of the Japanese food recipes exported to the world, and will continue to be made and rooted in the lives of the people of Nagano.