The word most frequently used in Aikido is ki. Ki is
a very convenient word because it has both a deep meaning connected with
nature and a light meaning which is used in daily life. It is very
difficult to define ki and even more difficult to translate it
into English. Therefore the word ki will be used in the
explanation of Aikido.
In oriental thought, it is said that in the beginning there was
chaos. The dust of chaos settled gradually to form the sun, the earth,
the moon, and the stars. On the earth, the elements combined to become
minerals, animal, and vegetable life. We call the chaotic conditions
before the universe took shape ki. We say therefore that all
things came from ki
Ki itself has neither beginning nor end, nor increase nor
decrease. Though it shape was changed, ki itself was never
changed. We can see many things around us all made from ki, and
when they lose their shape, their elements return to ki.
Depending on what you believe, you call it God, or Buddha, or Akua, or
some other name.
Aikido is the way of at-one-ment with cosmic power or ki.
That is the deep meaning of ki.
What is the light meaning of ki used in our daily life? A
good feeling, a bad feeling, a great feeling, timidity, vigor, courage,
a retiring disposition, et cetera --- these are terms used in our daily
life. In each word or phrase, the Japanese use ki as an integral
part. The reason is that a human being was created from ki of
the universe. While he receives ki, he is alive. Deprive him of
ki and he dies; he loses his human shape. So long as his body is
filled with ki and pours forth abundantly, he is vigorous and
filled with courage. On the contrary, when his body has run out of
ki, he is weak, cowardly, and retiring.
In Aikido training, we make every effort to learn to fill our body
with ki and use it powerfully. Therefore, we must understand
well the deep meaning of ki.
Koichi Tohei What is Aikido?, Rikugei Publishing House, Tokyo, 1962, page113