You have to make or buy dashi cubes first. You need to break it into four pieces, wash it with water and dry it in the sun. Go to a glass store and buy a Boehmer's meter. 1kg of salt to 4kg of water, measure the Boehmer's degree, and add more water than 19 degrees and more salt than 19 degrees. Wash and dry the sauce pieces into the sauce tank, to be arranged, add 19 degrees of salt water to submerge the sauce pieces covered with a plastic sheet and then covered with bamboo curtains or wooden rows with stones and other pressure. Fermentation for three months. After fermentation, take the juice and boil the soy sauce. The fermented soy sauce cubes are crushed and mixed well in a jar to continue fermentation for three months.