It’s hard to believe that such a benevolent mould could incite civil unrest, but in 1444, the ancient capital of Kyoto played host to the Bun’an Koji Riots. Unthinkable today in the context of the craft of sake brewing, but originally, brewers did not make their own koji. Instead, they had to rely on specialised manufacturers called koji-ya [麹屋], who produced and sold it to breweries and kept the knowledge and immense skill required to make good koji as closely guarded secrets. Breweries, of course, could not survive without good koji, so it was seen as a product with great profit potential.

The koji-ya were considered to have divine status by the famous Kitano shrine and formed trade associations or guilds known as za [座] which were governed by powerful people such as shrines, temples or wealthy aristocrats. The so-called koji-za [麹座] had the exclusive rights to manufacture and sell koji in western Kyoto and were backed by the authority of the Kitano shrine, known today as Kitano Tenmangu. Naturally, the Kitano koji-za was strongly opposed to any sake brewers taking the production of koji into their own hands, and the mighty backing of the shogunate ensured breweries were forbidden from doing so. Furthermore, any of the koji-ya who refused to join the za were banned from continuing to manufacture.

However, with the industry booming, some capital-rich brewers began to rebel against this monopoly and engage in their own koji production. The product supplied by the koji-za was expensive, and breweries wanted to make their own koji to attempt to improve the quality of their sake. Breweries and non-licensed koji-ya found making their own koji without permission prompted visits from the koji-za along with government officials there to destroy their muro, the special rooms where koji was made. This only served to inflame the situation, leading brewery-sympathetic monks of the Enryaku-ji temple to start calling for the abolition of the koji-za.

In response to this situation, the Muromachi Shogunate started to relax the strict koji-za system, which was naturally opposed by followers at Kitano Tenmangu. They barricaded themselves inside the shrine in protest, an act which escalated into a full-blown armed conflict with the Shogunate, afterwards named the Bun’an koji riots. The violence saw most of the shrine and its buildings burned to the ground, and also led to the demise of the koji-za, which ultimately paved the way for breweries to start making their own koji in the way they still do today. In the year following the riots, the koji-za monopoly was reinstated, but the Shogunate had already lost its authority in this regard, so the system gradually faded out.

It is somewhat humbling to think that, in the midst of all this fighting, the microorganisms were quietly and obediently just making koji. Next time you’re meditatively mixing your koji by hand, give thanks that you’re not being attacked by a katana sword-wielding samurai!