The earliest known depiction of Yin-Yang symbol belongs to the Trypillia culture and dates to 5200 B.C. The oldest preserved drawing of this symbol in China appears in the works of the Song era philosopher Zhou Dunyi (1017–1073 A.D.), author of the “Taijitu shuo” (Explanation of the Diagram of the Taiji). In a work entitled “A Geomedical Approach to Chinese Medicine: The Origin of the Yin-Yang Symbol” which was published in 2012 by Stefan Jaeger, we can read that: “The Yin-Yang symbol is tightly connected with the annual cycle of the earth around the sun,and the four seasons resulting from it. Using the gnomon, a pole stuck in the ground the ancient Chinese were able to record precisely the position and the length of the sun’s shadow throughout the solar year.This enabled them to precisely determine the length of the year, which they found to be about 365.25 days. Furthermore, they divided the circle of the year into segments, including the vernal equinox, autumnal equinox, summer solstice, and winter solstice. In addition, they used concentric circles around the pole, helping them to record the length of the sun’s shadow every day. As a result, they measured the shortest shadow during the summer solstice, and measured the longest shadow during the winter solstice. After connecting the measured points and dimming the part that reaches from summer solstice to winter solstice (Yin), they arrived at a chart like this one:
The resemblance between this chart and the modern Taichi-tu or Yin-Yang symbol is striking. This diagram provides visual evidence that the original Yin-Yang symbol describes the change of a pole’s shadow length during a year. This corresponds well with the meaning of “Taiji” in Chinese which is “Great pole”. NEXT PART >
