Can kumquat brew soy sauce? It is said that the Japanese brew soy sauce with kumquat, which is delicious. Does anyone know the brewing method?

You can't brew soy sauce by kumquat alone. Kumquat contains sugar and can be used to make wine and vinegar. Japanese orange vinegar is a condiment mixed with vinegar, soy sauce and orange juice, not brewed with oranges. Wine or vinegar brewed with kumquat or orange may not retain its original taste and aroma. Make orange vinegar with vinegar and soy sauce to make it taste like it, and then add an appropriate amount of orange juice.