Heart

The Japanese believe that "truth" lies "only" in  the inner realm as symbolically located in the "Heart" or belly (Hara). The Japanese believe that what is important and what is true toward human interactions lies in silence which is a kind of virtue similar to "truthfulness."

The words, "haragei and Ishin Denshin" symbolize Japanese attitudes toward human interactions in this regard. To understand the "Do" of a martial system as it relates to the Japanese view you should look to the Zen practice associated with traditional arts and the spirit of do (the way or path) which is characterized in the silence of meditation or mokuso. Zen is understood only at a deep and intuitive level. It can't be understood by words but through the constant practice we hear taught in the dojo and this is the actual explanation of the "why." Constant practice is focused toward meditation, quietude, and the emptying of our minds. It is a teaching of truth through a Zen connection which helps explain "Chinmoku" or silence in Japanese communications.

As you may be able to determine by this post the importance of learning the customs, courtesies and beliefs of a system both historical, especially as to traditional martial practice, and current are necessary to fully and completely understand the "what and why" of Asian martial systems and practice. It becomes critical if one actually goes to a traditional and Koryu based Dojo where the Sensei may still practice diligently these traits of the Japanese so one will understand and comprehend.

It is interesting that the Japanese look between the lines, into the void or spaces, for determining communications while we Americans tend to look directly at the lines seeking there what is actually in the white spaces between the lines and words, etc. It is like the great symbol of the Tai Chi, duality as in one side of the Earth the Japanese do it one way while at the opposite side of the Earth we do exactly the opposite.

The "do" practices also emphasize quietude and a grave atmosphere in which a controlled attitude contained within silence leads practitioners to the development of skill and success. Could this be because the silence or space between promotes present moment awareness where one looks toward the inner self to find and improve while the practice of the physical with a silence allows present moment awareness to perceive and feel the variances of the body so it may find balance and connect to the mind and thus the spirit of the person?

Silence in the dojo may also come from the Japanese identification with groups where the role of silence is creation of harmony and the avoidance of conflict. I can see this because most of the conflict I have witnessed usually rises to the inadequate communication, words, that folks exchange in a heated fashion.

Bibliography:
Davies, Roger J. and Ikeno, Osamu. "The Japanese Mind: Understanding Contemporary Japanese Culture." Tuttle Publishing. Tokyo, Japan. 2002.