Yin and Yang are often described in terms of the contrasting concepts they represent: Yin is quiet, shady, feminine, midnight, cold, interior, lethargic, and winter; Yang is loud, bright, masculine, midday, hot, exterior, energetic, and summer. But Yin and Yang are more than contrasts. They are also complements, and each is present within the other, as seen in the Yin-Yang symbol. Yin and Yang are two ends of a continuum: opposites blending gradually into one another. The concept of Yin is essentially “more Yin than Yang,” and the concept of Yang is essentially “more Yang than Yin.”
The expression Yin Yang is actually a simplification. In Chinese medicine, it is more accurate to speak of Yin Qi and Yang Qi, two aspects of the vital energy Qi (pronounced chee) that permeates the human body and is crucial to health. When Qi does not flow freely, due to imbalance of Yin Qi and Yang Qi or blockage of the channels through which it flows, ill health is the result. The dynamic tension between Yin Qi and Yang Qi is needed to maintain Qi balance-without the pull of Yin Qi, Yang Qi would not flow, and without the reciprocal pull of Yang Qi, Yin Qi would lose the force to continue pulling. The correct balance is continually aligning and realigning itself according to the needs of the body.