Kikkoman Corporation is a Japanese food manufacturer. Its main products and services include soy sauce, food seasoning and flavoring, mirin, shōchū, and sake, juice and other beverages, pharmaceuticals, and restaurant management services. Kikkoman has production plants and offices in Japan, the U.S., the Netherlands, Singapore, Taiwan, China and Canada.

Kikkoman is the most popular brand of soy sauce in Japan and the United States. The village of Sappemeer in Groningen, the Netherlands, is the European headquarters of the company. A plant on the site began operations in 1997 and now produces over 400 million litres of soy sauce per annum.

The West Japanese style soy sauce, called shoyu, has been a well-known condiment for over 300 years. Kikkoman is the largest shoyu manufacturing company in the world, and "the one most responsible for introducing shoyu to the West". Founded in 1917, it is based in Noda, Chiba Prefecture, Japan, and comprises eight family-owned businesses founded as early as 1603 by the Mogi and Takanashi families.

Kikkoman soy sauce is naturally brewed. After soaking in water for an extended period, soybeans are steamed at high temperature before they are mixed with crushed roasted wheat. Salt is added, which acts as an anti-bacterial agent and preservative. 

Next, a genus of the Aspergillus fungus is added to the mixture and left for three days to create shōyu koji, the base for the soy sauce. This base is then transferred to a tank and mixed with a saline solution, which creates a mash known as moromi. Several months of aging follow, when various organic processes occur including lactic acid, alcoholic and organic acid fermentation take place to create unique flavours. 

The moromi is then mechanically pressed through layers of fabric for around ten hours to extract the raw product. In the last part of the process, the raw soy sauce is left to separate for 3–4 days, then pasteurised using steam, which also stops any enzymic activity. The final product is then ready for inspection and bottling. Kikkoman has a distinctive bottle for its soy sauce, designed by Kenji Ekuan in 1961. 

According to en.wikipedia