Taijitu as the Joseon royal standard. Since the 1960s, "yin-yang symbol" is most widely applied to the "He tu" symbol which combines the two interlocking spirals with two dots. In the standard form of the contemporary "yin-yang symbol", one draws on the diameter of a circle two non-overlapping circles each of which has a diameter equal to the radius of the outer circle. One keeps the line that forms an "S", and one erases or obscures the other line. The design is also described "pair of fishes nestling head to tail against each other". The Soyombo symbol of Mongolia may be
School of Naturalists and Qi. In later periods, these epistemological theories came to hold significance in both philosophy and popular belief. This school was absorbed into the alchemic and magical dimensions of Taoism as well as into the Chinese medical framework. The earliest surviving recordings of this are in the Ma Wang Dui texts and Huang Di Nei Jing. Zou Yan (; 305240 BC) was an ancient Chinese philosopher best known as the representative thinker of the Yin and Yang School (or School of Naturalists) during the Hundred Schools of Thought era in Chinese philosophy. Zou Yan was a noted scholar of the