Masumi traces its origins to 1662, when the brewery was founded near Lake Suwa at the southern fringe of the Japan Alps in Nagano Prefecture. An abundance of pure mountain spring water, an excellent brewing rice called Miyamanishiki, and a local tradition of precision craftsmanship gave rise to the region’s full-bodied, flavorful and well-rounded sakes.
In 1920, the brewery's president, Masaru Miyasaka, appointed a 28-year-old sake prodigy named Chisato Kubota to the position of brewmaster. The two traveled throughout Japan in the manner of Zen monks, "knocking on the door of the master and seeking knowledge." This keen desire to elevate the quality of Masumi sake, combined with a shared openness of mind, was rewarded in 1936 when Miyasaka Brewing Company won the first of many top honors at the Japan National Sake Appraisal.
Masumi achieved even greater prominence in 1946 when brewmaster Kubota, discovering a lovely aroma emanating from one of the brewery's fermentation tanks, requested that an expert from the National Research Institute of Brewing be called in for consultation. Samples were taken, and it was soon confirmed that a new yeast variety, Association No. 7, had been discovered. In the sake world, discovering a new yeast is like receiving the Nobel Prize, and only a handful of breweries enjoy this distinction. With its gentle, pleasing aroma and ease of use, No. 7 soon spread beyond Nagano Prefecture, and today continues to be used by over half of the breweries in Japan. In 2002, Masumi released a redolent, old-style sake called "Nanago" (No. 7) in tribute to the famous microorganism to whom the sake world owes so much.
Masumi, which means transparency or truth, is the name of an 8th century bronze mirror kept at the Suwa Taisha shinto shrine. The Miyasaka family has provided the shrine with sake for centuries, so it was only fitting that their sake take the name of the shrine’s Masumi Mirror.