Taijitu prior to 1686. It combines several abstract shapes, including a "Taiji" symbol illustrating the mutual complement of man and woman. In socialist times, it was alternatively interpreted as two fish symbolizing vigilance, because fish never close their eyes. The modern symbol has also been widely used in martial arts, particularly t'ai chi ch'uan (Taijiquan), and Jeet Kune Do, since the 1970s. In this context, it is generally used to represent the interplay between hard and soft techniques. The dots in the modern "yin-yang symbol" have been given the additional interpretation of "intense interaction" between the complementary principles. Similarities can be
Yin and yang it were, at a deeper level in Nature, and were the most ultimate principles of which the ancient Chinese could conceive. But it so happens that we know a good deal more about the historical origin of the Five-Element theory than about that of the Yin and the Yang, and it will therefore be more convenient to deal with it first." He then discusses Zou Yan (鄒衍; 305 – 240 BC) who is most associated with these theories. Although Yin and Yang are not mentioned in any of the surviving documents of Zou Yan, his school was known as the