Miso is a traditional Japanese seasoning produced by fermenting soybeans with salt and a fungus, and sometimes rice, barley, or other ingredients. The result is a thick paste used for sauces and spreads, pickling vegetables or meats, and mixing with dashi soup stock to serve as miso soup. This factory was making miso the old way, no doubt the process has been modernized since then.
Haikyo: Abandoned Japan