Choshi, located at the easternmost edge of the Kanto Plain in northeastern Chiba Prefecture, is known for its beautiful coastline, fishing industry, and mild climate. The city is also famous throughout Japan for its traditional soy sauce. For centuries, Choshi has been an important center of soy sauce production, supported by its favorable natural environment, access to raw materials, and convenient waterways connecting the area with Edo, present-day Tokyo.
The soy sauce produced in Choshi has been carefully refined over generations. The combination of local resources, traditional brewing techniques, and the efforts of generations of brewers has established Choshi as one of Japan’s historic soy sauce-producing regions.
Choshi developed not only as a fishing town but also as an important center of soy sauce brewing. One reason was its distinctive climate. Offshore, the warm Kuroshio Current and cold Oyashio Current meet, helping create relatively small seasonal temperature differences and a mild, humid environment throughout the year.
These conditions were considered suitable for the growth of koji molds and yeast, which play an essential role in the fermentation process used to make soy sauce. Choshi also had convenient access to soybeans and wheat from nearby Hitachi Province, roughly corresponding to present-day Ibaraki Prefecture. This provided an important advantage in obtaining the main ingredients needed for brewing.
Transportation was another major factor. Soy sauce could be shipped toward Edo using the Tone River and Edo River, allowing Choshi’s products to reach the rapidly growing urban market efficiently.
Tamari soy sauce, considered one of the early forms of Japanese soy sauce, is traditionally said to have originated in Yuasa, Wakayama Prefecture, through the teachings of the monk Kakushin of Kokokuji Temple during the Kamakura period. After the establishment of the Tokugawa shogunate in Edo in 1603, demand for soy sauce grew rapidly as Edo became the political and economic center of Japan.
In 1616, Gemba Tanaka, a wealthy landowner in Choshi, began brewing soy sauce after receiving encouragement from Kuroemon Saneki, a sake brewer from Nishinomiya in present-day Hyogo Prefecture. This enterprise is regarded as the oldest soy sauce brewing business in the Kanto region and eventually developed into what is now known as Higeta Soy Sauce.
In 1645, Gihei Hamaguchi, originally from Hiro, near Yuasa in Wakayama Prefecture, moved to Choshi and began producing soy sauce. His business became the foundation of today’s Yamasa Soy Sauce, one of the city’s best-known soy sauce makers.
The name “Yamasa” is derived from the character for mountain, “yama,” combined with “sa,” associated with the brewer’s traditional crest.
In 1697, Gemba Tanaka established a method for producing koikuchi shoyu, or dark-colored soy sauce. This style became increasingly popular in Edo, where residents favored a rich, savory, and slightly sweet flavor over the lighter style associated with western Japan.
Soy sauce produced in the Kanto region became known as “jizukuri” or “local soy sauce” and eventually became highly popular in Edo, competing successfully with products shipped from western Japan.
The Hamaguchi family was also associated with significant contributions to local communities. In 1854, during the Nankai earthquake and tsunami, Gihei Hamaguchi was in Hiro, Wakayama. He recognized the danger of the approaching tsunami and helped save many villagers. The following year, he contributed to the construction of a seawall to help protect the community.
Hamaguchi later served in important positions, including as a financial official of the Kishu domain and chairman of the Wakayama Prefectural Assembly. He was subsequently invited by the national government to become Japan’s first Teiki-to, or head of the postal administration, where he contributed to the development of Japan’s modern postal system.
Yamasa received the title of “Superior Soy Sauce” from the Tokugawa government in 1864. In 1895, it was also selected as the first soy sauce producer in the Kanto region to receive official recognition as a supplier to the Imperial Household Ministry.
During the Meiji era, Yamasa established a research laboratory and began investigating the brewing process scientifically. This was an important step toward understanding fermentation and improving food production through modern scientific research.
Yamasa’s research contributed to the development of food science. In 1955, researchers identified inosinic acid as the umami component of dried bonito, and in 1957, they identified guanylic acid as the umami component of shiitake mushrooms. These discoveries helped advance scientific understanding of the savory taste known as umami.
In 1914, three major Choshi brewing families—the Tanaka family behind Higeta, the Hamaguchi family behind Jigamisa, and the Fukai family behind Kagitai—joined forces to establish Choshi Shoyu Co., Ltd.
The Hamaguchi Gihei Shoten business was incorporated in 1928 and became Yamasa Soy Sauce Co., Ltd., the company known today. In 1937, Choshi Soy Sauce formed a capital partnership with Noda Shoyu, now known as Kikkoman. In 1976, Choshi Soy Sauce changed its name to Higeta Soy Sauce Co., Ltd.
Choshi’s soy sauce industry became one of the successful industries of the local distribution economy of the Edo period. The availability of waterways was particularly important because it allowed large quantities of soy sauce to be transported from the production area to the major consumer market in Edo.
Soy sauce produced in Choshi was loaded onto boats and transported through the Tone River and Edo River toward Edo. Depending on the season and water conditions, the journey reportedly took approximately 10 days to one month.
Noda, another major soy sauce-producing area, had a transportation advantage because goods could travel to Edo using the Edo River alone. Under favorable conditions, this journey could take approximately eight hours.
Tsuchiura in Ibaraki Prefecture was another important soy sauce-producing town. The region had access to soybeans and wheat as well as convenient transportation through Lake Kasumigaura.
Traditional producers such as Kikkōmasa and Shibanu-ma Soy Sauce continue to represent this brewing heritage. Shibanu-ma is traditionally said to have been founded in 1688 by Shibanu-ma Shozaemon. Some other historic brewing families eventually left the soy sauce business and developed different types of businesses.
In Noda, numerous soy sauce producers, including the Mogi and Takanashi families, joined together and established Noda Shoyu, which later became Kikkoman. This consolidation helped Noda grow into one of the world’s largest centers of soy sauce production.
Yamasa Soy Sauce in Choshi also grew into one of the world’s largest individual soy sauce brewing companies. While preserving traditional brewing knowledge, the company has continued to pursue technological development and scientific research.
Choshi’s development as a soy sauce town was closely connected to its favorable climate, geographic location, access to raw materials, and excellent water transportation routes. From the Edo period onward, these advantages allowed the city to establish a lasting place in Japan’s soy sauce industry.
The history of Choshi’s soy sauce is also a story of innovation. Brewers such as Yamasa and Higeta not only preserved traditional fermentation techniques but also contributed to scientific research and community development. Today, Choshi remains an important destination for travelers interested in Japanese food culture and the long history behind one of the country’s most essential seasonings.