Kiai 気合 is a Japanese term used in karate for a short spirited shout, that is used to focus energy when performing an attacking or defending move.
The term kiai is a combination of Ki (life force), and Ai (meaning to blend or harmonize).
These are just my views on the karate kiai, I am sure other karateka will have differing views, but for me, Kiai is a focused short shout that concentrates physical, mental and emotional power into one point, at one time, but more importantly it helps develop a strong spirit.
Master Gichin Funakoshi the founder of Shotokan Karate said, ‘Sprit First, Technique Second’.
My sensei used to say ‘if you ever get attacked and knocked to the ground, it will be your spirit that will leave you there, or get you back up, and if your spirit is weak, you are in trouble!’
My Sensei would always encourage strong kiai. When training was really tough and you felt like you could not execute one more technique, Sensei would shout ‘more spirit’ and you would respond with a technique that you thought would be impossible with your current physical state. And that technique was always accompanied with a very spirited kiai.
So I believe that the Kiai helps develops a strong fighting spirit and helps take the karateka to the next level.
Without spirit, trying to defend yourself is almost impossible, you may have a lucky break, but if the ‘doo doo hits the fan’ and things get nasty, it’s not your perfectly practised techniques, but your spirit that will save you.
It was always explained to me that there are two kiai in karate, the main kiai and way more advanced silent kiai, explained below.
The attacking Kiai, which is the main kiai used by karateka during practice is used to shock the opponent whilst at the same time focusing mind, body and spirit on one point at the end of the strike, the sound is mainly a short sharp shout, ie, ya, eey, aiy, tay and develops from the hara (tanden).
The silent Kiai is the highest level of kiai in karate, many masters of the martial arts possess this kiai and some other rare individuals, it is almost like a projected aura, martial artists able to apply this silent kiai are sometimes able to stop people dead in their tracks, scare people and diffuse very dangerous situations all with what is sometimes referred to as a look.