The yin and yang are the two aspects in Daoist (also called Taoist) religious philosophy and later Daoist alchemical belief that everything stays in balance or harmony in nature and the universe. Both originate from the "Dao" (or Tao), meaning "The Way" or Existence, and from the innate balance gave birth to the Three, from which everything originates.
Chinese theory says that everything in the world can be identified as yin and yang in relation to one another. For instance, a light shower is less yang, and more yin, than a storm because it is gentler and seen as feminine and therefore, yin. The sun is more yang than the light shower because brightness is seen as masculine and therefore, yang. The basis of much of Chinese science in the pre-modern era was about the changes of yin and yang, and the Daoist religion is based around the concept in many senses.
The Yin and Yang diagram (Known also as a Taijitum, meaning "diagram of ultimate power" in Chinese, especially in eastern circles) shows a dark side (yin) and a light side (yang) each separate but flowing with the other, each containing a small amount of the other (shown as a "dot" of the opposite color).
Yin represents: dark, secret, passive, receptive, yielding, cool, soft, and feminine.
Yang represents: clear, bright, illuminated, evident, active, aggressive, controlling, hard, and masculine.
Neither side is seen as good or evil, both are considered necessary, the preferable state is when yin & yang remain in balance.
Yin and Yang are divided by the line which represents Qi, which is life force, the essence of being.
“ | The cyclical nature of yin and yang, the opposing forces of change in the universe, mean several things. First, that all phenomena change into their opposites in an eternal cycle of reversal. Second, since the one principle produces the other, all phenomena have within them the seeds of their opposite state, that is, sickness has the seeds of health, health contains the seeds of sickness, wealth contains the seeds of poverty, etc. Third, even though an opposite may not be seen to be present, since one principle produces the other, no phenomenon is completely devoid of its opposite state.[1] | ” |