Kiai may be fundamentally defined as, “Super Power” or “Spirit Letting”, although it is commonly recognized as, the “shout” or “yell”, so often heard in Karate-Do and other martial arts.

The word “Kiai”, is a combination of two Japanese words. The first, “Ki”, (called “Chi”, in Chinese), is representative of mind, spirit, intrinsic energy of life force, while “Ai” is the contraction of the verb, “awasu”, which means to unite or bring together.

“Kiai”, is made up of physiological and psychological principles.

On a physiological level, correct execution of “Kiai”, releases adrenal fluid into the blood stream, and aids in contracting and thus tensing the muscles. This is achieved by a sharp exhalation, which dispels approximately two-thirds of the air and forces the remainder into the lower abdomen. The “Kiai” is usually uttered at precisely the moment of impact. This is the time when the attacking surface of a technique makes a total contact with the desired target.

Psychologically, “Kiai” may be used to un-nerve or distract an opponent as well as to bolster a state of self-confidence in the mind of the person using “Kiai”.