Tamari originates from the Tokai region and was developed in the prefectures of Aichi, Mie and Gifu. It is usually made exclusively from soya beans, although in some traditions a small amount of wheat is added. The production of tamari is characterised by a unique method that differs from other types of shoyu. Instead of a loose mixture of soya beans and wheat, which is used for fermentation with koji in other types of shoyu, only soya beans are used to make tamari. After steaming, the beans are coarsely mashed and formed into small balls called mamekoji or misodama. These balls are then inoculated with koji spores and fermented for around 3-4 days.

Another characteristic feature of tamari production is the covering of the very firm mash with stones. White tamari stands out clearly from classic, savoury soy sauces. Unlike the more commonly known dark tamari and other soy sauces, which are made from soya beans, water and salt, white tamari is made exclusively from wheat, water and salt. Its maturing time is considerably shortened. This gives it its light colour and mild flavour.