●The significance of rice and soy sauce for the Japanese
Rice is one of the most important staples of Japan since ancient times.
For agriculture in Japan, rice is the most important crop and the percentage of income it represents as a single crop continues to be the highest. The Japanese are permanently bond to rice.
Soy sauce is a liquid condiment made mainly from grain (soy and wheat) and fermented through a number of brewing techniques. It is one of the base condiments for the Japanese.
The union of these two gives origin to senbei.
That is why senbei is such an important snack for the Japanese.