Later, during the Warring States period, the "School of Naturalists" (Yin-Yang School) synthesized these concepts with the theory of the Five Elements (Wu Xing). This integration created a powerful cosmological system used to explain everything from dynastic cycles to human physiology. By the Song Dynasty (11th century), the iconic "Taijitu" (Diagram of the Supreme Ultimate), the symbol we now call the Yin-Yang symbol, became the standard visual representation of these complementary forces.

Represents the feminine, darkness, passivity, cold, and rest. Yang (The Light Swirl):

is highly applicable to modern health and wellness, particularly in Traditional Chinese Medicine (TCM) and holistic health practices.

The idea is not that opposing forces are in conflict, but that they define each other. There is no "light" without "dark," no "up" without "down," no "masculine" without "feminine." The categories of Yin and Yang represent a duality of nature.