In Chinese philosophy, the concept of yin yang ([yin – simplified Chinese: ; traditional Chinese: ; pinyin: yīn] [yang - simplified Chinese: ; traditional Chinese: ; pinyin: yáng] eum-yang in Korean; often referred to in the west as yin and yang) is used to describe how seemingly disjunct or opposing forces are interconnected and interdependent in the natural world, giving rise to each other in turn. The concept lies at the heart of many branches of classical Chinese science and philosophy, as well as being a primary guideline of traditional Chinese medicine, and a central principle of different forms of Chinese martial arts and exercise, such as baguazhang, taijiquan, and qigong. Many natural dualities – e.g. dark and light, female and male, low and high – are cast in Chinese thought as yin yang.
According to the philosophy, yin and yang are complementary opposites within a greater whole. Everything has both yin and yang aspects, which constantly interact, never existing in absolute stasis. Compare wuji.
Yin and yang is symbolized by various forms of the Taijitu. Yin and yang are thought to arise together from an initial quiescence or emptiness (wuji, sometimes symbolized by an empty circle), and to continue moving in tandem until quiescence is reached again. For instance, dropping a stone in a calm pool of water will simultaneously raise waves and lower troughs between them, and this alternation of high and low points in the water will radiate outward until the movement dissipates and the pool is calm once more.
Yin–yang, thus, always has the following characteristic: yin and yang describe opposing qualities in phenomena. For instance, winter is yin to summer's yang over the course of a year, and femininity is yin to masculinity's yang in human relationships.