The terms ch'i and ki (as related, for example, to martial arts) are indistinguishable. Although it has a multitude of meanings, ki or ch'i has been described as the breath, spirit or nature of things. In Taoism, ch'i is the life force, the vital or primordial energy which, as cosmic spirit, diffuses all creation and gives it life. Every individual has a reservoir of this energy from birth, located in the physical sense at the navel, the so-called "ocean of breath" where exercises aimed at prolonging life are centred, the ch'i-hai. Normal living depletes this store of energy and leads to sickness and death. Different techniques, for example those of Taoist alchemy, concentrate on preserving, nurturing and replenishing ch'i, whether in the physical, mental or spiritual sense; and lead to health, longevity or immortality at the appropriate level. In the physical sense, exercises concentrating on control of breath may lead to re-establishment of emotional well-being and balance within the neurohormonal system.
In neo-Confucianism the concept was expanded and precised to indicate that which causes the physical manifestation (variable) of the metaphysical (always good). A flawed ki thus indicates a flawed moral nature; purification of ki leads to enlightenment, with consciousness and action in perfect unity.
Ki energy is both personal and impersonal, concrete and universal. Transcending time and space, it is the basic creative energy or force in life. As a psychophysical energy important in the martial arts, ki energy is developed by breathing exercises and implemented by concentration of the will. Ki is twofold - the unity of the individual-universe and the free and spontaneous expression of breath-power. The former, inheriting the ideas of ancient Chinese thinkers, is realized through unifying ki, mind and body in, for example, aikido training. It acts as defence against physical attack and may be used at a distance. The kiai shout focuses all the bodily and spiritual energy into one sound, unifying the proponent's powers and disconcerting the opponent.
Harmony of ki, or ai-ki, is manifest when mind and body are unified, its subtle working is the maternal source that affects changes in breath. As delicate changes in breath power occur spontaneously, proper technique flows freely.
Awareness of delicate changes may show fierce and potent or slow and stolid movements of ki in the void, leading to discernment of the degree of concentration or unification of mind and body. Ki can be taken to mean mind, spirit or heart, and thus to have ki out of order in some way means a diminished state of consciousness. This may be insanity, nervousness, depression; it may be an emotional condition (quick tempered, shy). It is the ki and not the individual that is referred to in these cases.
·Koichi, Tohei Book of Ki: co-ordinating mind and body in daily life
·Reed, William Ki: a practical guide for Westerners
·Siu, R G H Ch'i: a neo-Taoist approach to life (1974)
·Yang, Jwing-Ming The Root of Chinese Chi Kung (1988)