Junmai Sake is brewed using only rice, water, yeast and koji. There are no other additives. To qualify as a Junmai, there is technically no minimum milling requirement, but the sake must be the “pure rice” style… no added distilled alcohol allowed.
Honjozo Sake must be milled to 70% or less of it’s original size and as far as ingredients go, it contains a small amount of distilled brewer’s alcohol, which is added to the sake to achieve different flavor & aroma profiles.