Shoyu - Soy Sauce -

@The origin of the soy sauce was called "Hishio". The "Hishio" was
made from various kinds of bacteria existed in the air, such as certain
malt bacteria. They entered inside the materials, such as the salted
fish or meat, and altered the taste of the food. During the era
when people go fishing and hunting for their living, people didn't require
any seasoning for their meal because the meat or fish they caught had
the salty taste on it already. However, after the era when people began to
eat rice and wheat, people asked for the seasoning of salt taste
because there were no salty taste on the rice and wheat.
So people made "Hishio", and ate it with fish, meat, and vegetables.

After a soy bean was conveyed in 500's by China, the new "Hishio" was
made from a soy bean, rice and wheet (how to make was conveyed
from China and the Korean Peninsura), and it is said this is the ancestor
of soy sauce.
@"Hishio" came to be sold as an article in the Heian era, and it was the
expensive seasoning that only a person of a high social position could buy.
In the Kamakura era, a Buddhist priest discovered the liquid while he pickled special miso, it was delicious and came to use this liquid as a seasoning.
This became a hint, and soy sauce became to make. In the Muromachi era
malt became to be sold in the shop, and people got possible to make "hishio" without relying to bacteria. And a word of "soy sauce"
appeared for the first time in 1520's. "The sop soy sauce",
the liquid which was discovered in the temple, has begun to
be made in the Kii area.
@In the Edo era, the "sop soy sauce" came to be made
in all parts of Japan, and strong soy sauce came to be
made in Shimousa (old Chiba), and light soy sauce came
to be made in Harima (old Hyogo).
@When soy sauce spread out, people came to season it
during cooking, and Japanese foods such as boiled dishes
appeared in sequence. Soy sauce comes to be
produced in large quantities in a factory from the
Meiji era, and it is exported to about 100 countries
including U.S.A..