In order to understand why this brewery is so special, we need to take a quick dive into the world of Liquor Tax Act in Japan. Stay with us here, because this might be the only time where a story about taxes will keep you on the edge of your seat, because it's really a tale about a plucky underdog coming out on top. Back in the 1980's, the word "Ginjo" was fairly unknown to the regular sake drinker. The very few Ginjos that were commercially sold were incredibly expensive, and usually bought only to be given as gifts. Sake in Japan back then were not sold classified by their types, like Ginjo, Daiginjo, Junmai, but rather in three categories of Special Class, First Class, Second Class. This classification was not based on how good the sake was, but simply, if brewers wanted their sake to be sold as First Class or higher, they had their sakes tested by the government to ensure its quality, and if it passed, they were sold as First Class or Special Class. They were also taxed accordingly; the higher the class, the higher the taxes.
In order to compete with the wealthy national companies who were all clamoring to get their sakes classified as First Class, Dewazakura, a small local company, brewed a beautiful Ginjo sake called Oka Ginjoshu. They did NOT have it appraised by the government, and sold them as Second Class, and therefore, at a more affordable price, allowing, for the first time, regular people to enjoy ginjo sake. In a blink of an eye, the fruity, light, crisp sake was a sensation; people "discovered" Ginjos, triggering the Ginjo Craze, and Oka Ginjoshu became synonymous with Ginjo.
Also, fun little tidbit: Dewazakura's sakes were the model for the scent of SK-II beauty products.