Abstract
In this study, two kinds of shoyu (soy sauce), Usu-shoyu and Usukuchi-shoyu, used in recipes in 93 cookery books published during the Meiji, Taisho, and beginning of Showa periods were examined to elucidate whether Usukuchi-shoyu was formerly named Usu-shoyu.
Three descriptions of Usu-shoyu were observed in eight of the books; three of these described it as a light coloured soy sauce (type-1), four described it as soy sauce diluted with dashi (type-2), while one described it as soy sauce diluted with water (type-3).
After 1916, the number of mentions of Usu-shoyu decreased (203 before, 88 after) and that of Usukuchi-shoyu increased (5 before, 88 after), in parallel with the increase in the number of recipes (0 before, 88 after) indicating the volume of shoyu used in dishes.
From the description of eight of the recipes in three books published after 1916 and investigation of the NaCl concentration of those dishes, it was deduced that the Usu-shoyu used in one of those recipes was synonymous with Usukuchi-shoyu, and the one used in the seven other recipes was similar to Usukuchi-shoyu (type-1 Usu-shoyu). Thus, it can be concluded that Usukuchi-shoyu was formerly called Usu-shoyu.
It is assumed that the change from Usu-shoyu to Usukuchi-shoyu resulted from the ambiguity of the former word.
