Otherwise known as Aspergillus oryzae.
If you didn’t know, koji is a sporulating mould that grows on starches in very specific humidity & moisture conditions. It has been bred for hundreds of years for the production of garums, miso & amazake. And in turn rice vinegar & sake.
Here at Scratch we inoculate our own koji spores in a cedar cabinet. We can supply fresh koji in limited amounts should you want to get your hands on some.