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
Yin and yang Yin Yang Jia (Yin and Yang School) Needham concludes "There can be very little doubt that the philosophical use of the terms began about the beginning of the -4th century, and that the passages in older texts which mention this use are interpolations made later than that time." In spite of being used in a modern context to justify egalitarianism under the notion of both yin and yang being "necessary", in practise the concept of yin and yang has led to justification for China's patriarchal history. Particularly under Confucianism, yang (as the sun principle) is considered superior to "yin" (the