Miso is a traditional Japanese seasoning (thick paste), produced by fermenting soybeans with salt and kōji, at its most basic.
To know more about miso & DIY miso recipe,

Koji is not only a key ingredient for Japanese fermented food but also it is getting common among chefs to use koji as a tenderizer / umami enhancer in any kinds of culinary .

Fermented foods have been a well-established in everywhere in the world for thousands of years. In recent years there’s been a greater push to raise koji awareness, especially with NOMA in Copenhagen and Jeremy Umansky with Koji Alchemy.