The concept of ki is one of the most difficult associated
with the philosophy and practice of aikido. Since the word "aikido"
means something like "the way of harmony with ki," it is hardly
surprising that many aikidoka are interested in understanding just what
ki is supposed to be. Etymologically, the word "ki"
derives from the Chinese chi. In Chinese philosophy, chi was
originally supposed to be that which differentiated living and
non-living things. But as Chinese philosophy developed, the concept of
chi took on a wider and wider range of meanings and applications. On
some views, chi was held to be the most basic "stuff" out of which all
things were made. The differences between things depended not on some
things having chi and others not, but rather on a principle (li,
Japanese = RI) that determined how the chi was organized and functioned
(the view here bears some similarity to the ancient Greek matter-form
Modern aikidoka are less concerned with the historiography of the
concept of ki than with the question of whether or not the term
"ki" denotes anything real, and, if so, just what it does denote.
There have been some attempts to demonstrate the objective existence of
ki as a kind of "energy" or "stuff" that flows within the body
(especially along certain channels, called "meridians"). So far,
however, there have been no reputable studied published in peer-reviewed
scientific journals that substantiate such claims. This does not, of
course, settle the question decisively against the existence of
ki, but, just yet, the evidence does not support existence claims
There are a number of aikidoka who claim to be able to demonstrate
the (objective) existence of ki by performing various sorts of
feats. One such feat that is very popular, is the so-called
"unbendable arm." In this exercise, one person, A, extends her arm,
while another person, B, tries to bend her arm. First, A makes a fist
and tightens the muscles in her arm. B is usually able to bend the arm.
Next, A relaxes her arm (but leaves it extended) and "extends
ki" (since "extending ki" is not something most newcomers
to aikido know precisely how to do, A is often simply advised to think
of her arm as a fire-hose gushing water, or some such similar metaphor).
This time, B finds it (far) more difficult to bend the arm. The
conclusion is supposed to be that it is the force/activity of ki
that accounts for the difference. However, there are alternative
explanations expressible within the vocabulary or scope of physics (or,
perhaps, psychology) that are fully capable of accounting for the
phenomenon here. In addition, the fact that it is difficult to filter
out the biases and expectations of the participants in such
"experiments" makes it all the more questionable whether they provide
reliable evidence for the objective existence of ki.
Not all aikidoka believe that ki is a kind of "stuff" or
"energy." For some aikidoka, ki is an expedient concept --- a
blanket-concept that covers intentions, momentum, will, and attention.
If one eschews the view that ki is a stuff that can literally be
extended, to extend ki is to adopt a physically and
psychologically positive bearing. This maximizes the efficiency and
adaptability of one's movement, resulting in stronger technique and a
feeling of affirmation both of oneself and one's partner.
Irrespective of whether one chooses to take a realist or an
anti-realist stance with respect to the objective existence of
ki, there can be little doubt that there is more to aikido than
the mere physical manipulation of another person's body. Aikido
requires a sensitivity to such diverse variables as timing, momentum,
balance, the speed and power of an attack, and especially to the
psychological state of one's partner (or of an attacker).
In addition, to the extent that aikido is not a system for gaining
physical control over others, but rather a vehicle for self-improvement
(or even enlightenment), there can be little doubt that
cultivation of a positive physical and psychological bearing is an
important part of aikido. Again, one may or may not wish to describe
the cultivation of this positive bearing in terms of ki.
The Aikido Primer