Tai Chi, also known as Shadow Boxing, is one of the major branches of traditional Chinese martial arts. Its name is derived from the philosophical term, “Tai Chi,” the first known written reference of which appeared in the Book of Changes over 3000 years ago during the Zhou Dynasty (1100-1221 BC). This book says that “in all changes exists Tai Chi, which causes the two opposites in everything.” Tai Chi means the ultimate of ultimate, often used to describe the vastness of the universe. The essential principles of Tai Chi are based on the ancient Chinese philosophy of Taoism, which stresses the natural balance in all things and the need for living in spiritual and physical accord with the patterns of nature. According to this philosophy, everything is composed of two opposites, but entirely complementary elements of yin and yang, working in a relationship in perpetual balance. Tai Chi consists of exercises equally balanced between yin and yang.