In the mists of China's distant past, well before its written history, the idea of how the universe was conceived, and along what principles its cosmic forces operated, had woven itself into the very fabric of chinese belief systems.
The first principle or beginning was and is the Wuji state, which means no extremities or perfect balance. This pool of energy generates and sustains the flow of the supreme universal energy. This cyclic merging and renewing of the cosmic forces has been termed the interplay of Yin and Yang, the symbol of Tai Chi Chuan.

Yin is a concept that includes but is not restricted to the following characteristics. Magnetic, feminine, water, darkness, passive, moonlight, receptive, cool, yielding, nurturing and night.
Yang is electric, masculine, fire, light, aggressive, sunlight, expressive, warm, opposing, protective and day.

These two are in a continuous state of exchange, merging and unmerging, moving from one polar extreme to the other. We can see the concept of Yin and Yang by the way properties change. Hot becoming cold, dark becoming light, sun and moon, positive and negative polarity, fullness and emptiness, wet and dry.

Since the two streams of energy are governed by the laws of harmony, cycles and balance, they are complimentary to each other. they in turn are governed by The Dao, the Way of Heaven
Therefore the Dao is the guiding principle that creates, animates and transforms everthing that is of the Universe. From the most basic building units at the atomic level, to the interplay of cosmic forces that radiate over our earthly sphere and other celestial bodies in a synergy of phenomena.

This concept of a primal life force is reflected in other cultures, in ancient Egypt it was called Ka, in India prana, the Hebrews called it the spirit of the Lord. It was here long before us and will be everywhere for eternity because it is the Source of All

The first recorded mention of the theory of Yin and Yang was in the chinese classic "I Ching" the Book of Change believed to have been written in 1122 B.C
This gives a historical basis of more then 3000 years to Qigong and Tai Chi Chuan theory.