kiai

In Japanese martial arts a is a short shout uttered when performing an assault.

Traditional Japanese dojo generally uses single syllables beginning with a vowel. The practice has become a part of Asian martial arts in popular culture, especially in martial arts films, in writing often rendered in variants such as Hi-yah!, Aiyah!, Eeee-yah! or Hyah!. A kiai is usually not the word "kiai" itself.