YIN-YANG CONCEPT.

Yin-Yang (dualism) is one of the dominant concepts shared by different schools throughout history of Chinese philosophy. The most enduring interpretation is related to the concept of Qi (Chi=vital energy).
According to this interpretation, Yin-Yang is seen as Qi operating in the universe.
The earliest characters for Yin-Yang (dualism) are found in inscriptions made on oracle skeletal remains of various animals used in ancient China at least as early as the 14th BC. In this inscriptions, Yin-Yang are descriptions of natural phenomena such as weather conditions, and the movements of the sun. The sunlight during the day is Yang and lack of sunlight at night is Yin. Yang refers to height, brightness and the South side of a Mountain, and Yin refers to a closed door, darkness and the South bank of a River and the North side of a Mountain. This sun-based daily pattern led to a conceptual claim: Yang is movement (Dong) and Yin is rest (Ji'Ing).
It was believed that there were 6 heavenly influences (Qi), which upon descending produced the 5 tastes, going forth in the 5 colors, and were verified in the 5 notes; but when they were in excess, they produced the 6 diseases. Those 6 influences were denominated: Yin, Yang, Wind, Rain, Darkness, and Brightness. In their separation, they formed the 4 seasons; in their order, they formed the 5 elements, When any of them were in excess, they ensured calamity. An excess of the Yin (negative) led to diseases of cold; and excess of the Yang (positive), to diseases of heat.
Despite the differences in the interpretation, application, and appropriation of Yin-Yang (dualism), three basic themes underlie the concept: 1)Yin-Yang as the coherent fabric of nature and mind, exhibited in all existence, 2) Yin-Yang as interaction (Ji'Ao) between the waxing and waning of the cosmic and human realms, and 3) Yin-Yang as a process of harmonization ensuring a constant, dynamic balance of all things.
Yin in its highest form is freezing while Yang in its highest form is boiling. The chilliness comes from heaven while the warmness comes from the earth. The interaction of these two opposites establishes harmony, so it gives birth to things.
Yin-Yang is complementary, emblematic of valuable equality rooted in the unified, dynamic, and harmonized structure of the cosmos.
Yin-Yang schools of teaching existed already during the "Spring and Autumn" (770-481BC) and "Warring States"(403-221BC) periods. Alongside with this Yin-Yang school, 5 others known from the same periods (Kong-Fusian, Mohist, Legalist, Fatalist, and Daoist) defines the theory of the study as "the investigation of the art (Shu) of Yin-Yang." The study focused on omens of luck and explored the patterns of the 4 seasons, and methods of prediction and astronomy. Just as the Confucians (Ru-Jia) arose from the ranks of Ru-Shi (scholar-gentlemen) who excelled at ritual and music), those of the Yin-Yang school came from the Fang-Shi (recipe-gentleman) who specialized in various numerological disciplines known as Shu-Shu (number-arts). This discipline included astronomy (Tian'Wen), calendar-keeping (Li-Pu), Five Faces correlative theory (Wu'Xing), Tortoise-shell interpretation (Zhu-Guai), fortune-telling (Za'Zha) and face-reading (Xing'Fa).
By the Han dynasty (202BC-220CE), Yin-Yang (dualism) was associated with"Five Faces"(Wu'Xing) correlative cosmology. According to the "Great Plan,"a chapter of the "Classic of Documents" (Shu'Jing), Wu'Xing refers to material substances that have certain functional attributes: Water is said to soak and descend; Fire is said to blaze and ascend; Wood is said to curve or be straight; Metal is said to obey and change; Earth is said to take seeds and give crops. Wu'Xing is used as a set of numerological classifiers and explains the configuration of change on various scales. The Yin-Yang/ Wu'Xing teaching -an early Chinese attempt in the direction of working out metaphysics and cosmology- was a fusion of these two conceptual schemes applied to astronomy and the mantic arts.
In the Tai Xuan (The Great Dark Mystery), writen by Yan Xion, his chief philosophical writing, the term Xuan describes dark, black, mysterious, profound, abstruse or hidden. The writer, however, used the term Xuan to refer to the hidden fountainhead or initial state, out of which things emerge and the mysterious process through which they unfold. The Tai Xuan, then, is based on an evolving sequence of figures that, when taken together, map out the cycles of transformation underlying all things. Each figure-image- circumstance is articulated through an evolving series of statements that describes and appraises the unfolding of the situation and the meaning of the image.
Yang Xiong, a prolific yet reclusive court poet, his writings and tragic life spanned the collapse of the Han dynasty (202BC-9CE) and the brief and catastrophic usurpation of the throne by the imperial regent Wang Mang (9-23CE). He is best known for his assertion that human nature originally is neither good nor depraved but rather comes into existence as a mixture of both. As a social critic and classical scholar, he is considered to be the chief representative of the Old Text School of Kong-Zi'anism.
Another book of the same author is "Words to Live By"(Fa Yan). The Fa Yan focus on the perennial Kong-Zi (Confucian) theme of self-cultivation while emphasizing the importance of learning, friendship, role models, rites and music, the natural tendencies, the human virtues, the value of the classics, the princely person, the sage, ruling, filial responsibility, and so forth. Also we can find discussion of concepts and themes usually associated with the way (Dao), potency (De), spontaneity (Zi'Ran), non-coercive action (Wu'Wei), minimizing desire, the vanity of the desires of wealth, office and renown, and the challenges of surviving and maintaining one's integrity in a time of disorder.