In this excerpt from the intriguing documentary Mind, Body and Kick-Ass Moves, a Japanese martial arts expert uses the power of his kiai to ring a heavy temple bell.
According to Master Sasaki:
The body is approximately 70% water. An expression of kiai causes ripples in this water, which stills the opponent’s energy. It’s an instantaneous release of great power.
The Chinese concept of Qi is ambiguous. Kiai as used by the Japanese is an actual force; it’s more concrete.
Another self-identified kiai master entered a challenge match against an MMA fighter. Here are the results:
MMA vs. Kiai-jutsu