Why do we kiap? Kiaps are nothing new to Korean or Japanese martial arts. In Japanese it is called Kiai (気合). The reasons behind Kiaps varies from organization, styles and even schools. There are many ways or sounds of the Kiap/Kiai. They range from a ‘grunt to a
loud yell or other sounds and some even yell “kiai” etc. Grandmaster Son, Duk-sung (June 17, 1922 – March 29, 2011) formally of the World Taekwondo Association/ChungDo Kwan was known for shouting “utz” and promoted it in his publications and classes.
Of course, the Korean concept comes directly from the Japanese influences as Japan had a huge influence in the development of modern Korean martial as from Taekwon-Do (태권도/跆拳道) and Hapkido (합기도/合氣道) and is used extensively in Kumdo/Kendo (검도 剣道) too . A Kiap/Kiai is essentially a “war cry” and every society and military has different versions of it. We have seen it in all sorts of movies from Mel Gibson’s “Braveheart” and “We were Soldiers” to movies like the “Last Samurai” and “TaeKukk Ki.”
It is a pretty known fact that with proper timing the actual act of a Kiap at the time of the execution of the techniques, it helps generate power. Partly because of the physics involved.
The two terms “kiap” and “kiai” are the same as “Hapki” (hapkido) and “Aiki” (Aikido) but transposed. The terms basically mean “coordination spirit/united spirit”. Some styles and organizations promote it more as a meta-physical aspect of martial arts, but others more as a practical application at the time of the execution of techniques. Try any technique on a target. The first one take a breath and hold it and execute your technique (doesn’t really matter what technique you use) and then use the exact same technique but this time do a kiap/kiai at the time of the technique you will clearly feel and see the difference.
(As a side note: The I.T.F. have never used any kiap in the patterns Officially. General Choi never wanted them incorporated, it was only I.T.F. instructors, from the older Kwans that put them in. E.G. GM Jhoon Rhee, GM Cho, Hee-il etc. Only in the last couple of years has the I.T.F. under Choi, Jung-hwa put them in the tuls/patterns.)