Shoyu and Hospitals: The Emergence of Low Sodium Soy Sauce in Modern Japan

Abstract

This study is a part of a collaborative research project with Angela Ki-che Leung to explore the histories of soy sauce production and technologies in modern East Asia. In the larger project, we plan to study the ways soy sauce transformed from a domestically produced and consumed food to an item commercialized by local and regional artisans, and finally to a global merchandise, looking at the production and manufacturing processes connecting China, Taiwan, Hong Kong, and Japan from the late nineteenth century to the present. In this study, I propose to explore one aspect of soy sauce communities in detail to examine the diverse systems of production support infrastructures—hospitals and its unexpected collaborations on low-sodium soy sauce. While the creation of modern hospitals and clinics in Japan have been studied elsewhere, I am interested in the wide range of clinics that are often founded for workers (and their families) of soy sauce breweries that also served as community hospitals. For example, the Kikkoman Corporation, located in Noda-City, Chiba Prefecture, began by establishing clinics for their workers in 1862. By the second decade of the twentieth century, the clinic had expanded and was re-named Noda Hospital in 1914, and in 1973, it was renamed the Kikkoman General Hospital. Other producers, such as Hamada Shōyu, located in Kojima-City, Kumamoto, were unable to finance their own private clinic, but had special arrangements with a local clinic for all of its workers, and often delivered soy sauce in addition to monetary payment for treatments. While this study originally began as interest in industrial hygiene and illnesses specific to modern soy sauce production, it unexpectedly uncovered the relationship between producers and medical clinical staff, where the request for low-sodium soy sauce was raised to the Hamada Shōyu from its local clinic for its hospitalized patients in 1973. Kikkoman had already begun research and development for such a product in the late 1950s due to a request for a “health soy sauce” (originally dubbed hoken shōyu for regulatory reasons) from not its own clinic, but from the University of Tokyo Medical Faculty and Hospital. These products, later renamed “reduced sodium soy sauce” (gen’en shōyu), required new forms of soy sauce production to lower sodium levels without impacting the overall flavor. These innovations differed by the manufacturer and the region, and demonstrated varying approaches—ranging from more chemical interventions to shifting completely to sole use of natural salts—to deal with what was seen as an increasing nutritional concern over this everyday product.