Japanese Soy Sauce and its history in the Edo period

Having looked over the Edo history, there are many fermentation products invented during the Edo period and one of the most indispensable products for Japanese is Shoyu - soy sauce. While Japanese use soy sauce as a daily essential seasoning for many dishes, how many kinds of soy sauce do you think we have in the market? How many brands do you think we have in Japan? 

According to the JAS (Japan Agricultural Standard), there are five kinds of soy sauce in the market; Koikuchi (regular soy sauce), Usukuchi (light color soy sauce), Tamari soy sauce, Saishikomi (double-fermented soy sauce) and Shiro (clear soy sauce). This definition was determined based on our conventional life-style and the government successfully streamlined the categories into these five. The majority is Koikuchi (regular soy sauce) that represents 84% of the market share. The next is Usukuchi (light color soy sauce) that presents 13% of the market. The other 3 kinds of soy sauce compete against each other in the rest 3% of the market. 

Here are the definitions.

(Image Source: Soy Saurce Information Center Website)

　

Koikuchi (Regular):

Koikuchi shoyu is made from cultured mold (Koji) with approximately equal portion of soybeans and wheat and brine after going through several months’ fermentation process.

Usukuchi (Light Color): 

Usukuchi shoyu is made from cultured mold (Koji) containing more wheat and less soybeans than Koikuchi shoyu. To make the color lighter than Koikuchi, about 10% more salt is used; on the contrary, saccharified rice-koji (Amasake) is sometimes added to moderate saltiness. Fermentation period is also shorter than Koikuchi. 

Tamari: 

Tamari shoyu is made mostly from soybeans with only a small amount of wheat with a ratio of 10:1-2 or no wheat (wheat-free version). Tamari is regarded as the original formula of soy sauce. Tamari mainly appears in Chukyo (Nagoya) region.

Saishikomi (Double-fermented): 

Saishikomi shoyu is made by cultured mold (Koji) in raw soy sauce instead of usual brine. Because of this process, it tends to have richer and stronger Umami and sweetness than Koikuchi. Saishikomi appears in Yamguchi (Chugoku) region.

Shiro (Clear): 

Shiro shoyu is very light in color and is made mainly from wheat with very little soybeans in a ratio of 10:1-2. Fermentation period is much shorter and this soy sauce appears in Chukyo (Nagoya) region.

Interestingly, the current Koikuchi soy sauce was being developed between 17th and 18th century after Tokugawa Ieyasu founded the Edo bakufu. Since the Edo township started expanding with growing population, many products had been brought from Kamigata (Osaka) to fulfill the consumption. Soy sauce was one of them called “Kudari-mono (shipping down to east from west) Shoyu” and the major production locations of soy sauce at that time were Wakayama and Hyogo. Japanese soy sauce is said that the original form was accidentally founded during Miso production in Wakayama. This original form of soy sauce was close to Tamari and it is believed that Wakayama is the birth place of Japanese soy sauce. 

At the beginning of soy sauce introduction to Edo, about 80% of soy sauce were from Kamigata and about 20% was supplied from local producers near Edo such as Chiba and Ibaragi, and so forth. After brought to Edo, soy sauce was continuously being improved by adding wheat for better flavors and aroma by Kanto producers. As the Edo people not only ate fresh fish from the Edo Bay but also needed stronger flavored seasoning, this modification was well accepted to become the current Koikuchi style. This evolved soy sauce became more popular and, by the end of Tokugawa shogunate, soy sauce supply to the Edo area was 80% locally and 20% from Kamigata.

There are also some records that show exports of soy sauce during the Edo period. However, the official export of soy sauce was observed in 1868 when the first Japanese immigration delegation started to Hawaii. Since then, Japanese soy sauce has been exported to many foreign countries wherever there are Japanese people.

(Conpura ceramic bottle traded at the Mercari) Source: www.mercari.com

(Reproduction of Conpura bottle)

Currently we still have approximately 1200 brands in Japan and the top 5 major brands represent 50% of market share. Now you can check how many kinds and brands you can see at your local supermarkets and you may be able to find more unique kinds of soy sauce in the market. Let’s try to find your favorite soy sauce!