Shōyu: A Source of Flavor Essential to Japanese Cuisine

Koikuchi dark soy sauce (left) is the main type used in the Kantō region, while usukuchi light soy sauce (right) is preferred in Kansai. (© Pixta)

The cover of the second volume (left) of the 1597 Setsuyōshū Japanese dictionary, along with the entry for soy sauce, using the kanji 醤油. Its given reading is shōyu. (Courtesy National Diet Library)

A shōyu brewery in Tōnoshō, Chiba, that still continues to produce the condiment using traditional methods. (Courtesy Chiba Prefectural Tourism and Local Products Association)