Shoyu koji (醤油麹) is a fermented seasoning that combines soy sauce and koji. It adds umami, sweetness, complex aroma, and thickness to soy sauce and can be used in various dishes. Its flavor is characterized by its umami richness. Shoyu koji is said to contain 10 times more glutamic acid, a flavor component, compared to shio koji.

Of course, the original taste and aroma of soy sauce are also present. However, the saltiness becomes milder, and you may notice a stronger umami flavor and sweetness. In addition, the aroma derived from koji adds complexity and richness to the taste.