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 contracting) are thought of as physical manifestations of the duality symbolized by yin and yang. This duality lies at the origins of many branches of classical Chinese science and philosophy, as well as being a primary guideline of traditional Chinese medicine, and a central principle of different forms of Chinese martial arts and exercise, such as baguazhang, taijiquan (t'ai chi), and qigong (Chi Kung), as well as appearing in the pages of the "I Ching". The notion of a duality can be found in many areas, such as Communities of Practice, but in this context yin and yang are better