Tai chi is an internal martial art tradition. Traditionally practitioners did tai chi to develop their martial arts skills. Today it is practiced primarily for spiritual cultivation and/or for its outstanding and well-documented health benefits.
The gentle, flowing movements of tai chi help release mental and physical tension, increase vitality, focus the mind, improve circulation, foster spiritual awareness, and encourage inner peace.
Read about the many, many health benefits of tai chi in this article from Harvard Medical School.
Tai chi is usually translated as "Supreme Ultimate." (Chi is the Wade-Giles transliteration of ji (pinyin) and is not to be confused with qi (pinyin) or ch'i (Wade-Giles), which means "life energy.")
The term Tai Chi is used in Chinese philosophy, particularly Daoism, to describe the evolution of the universe. Wu ji is a state of emptiness and nothingness, and refers to the state of being before the universe came into existence. From wu ji came tai chi, the point at which the universe came into existence in its initial, gaseous state.
Tai chi, or the universe, expanded and separated, with clear air rising and turbid air falling and thus forming liang yi, “the two sides” – heaven and earth, light and dark, hot and cold, male and female etc. – also known as yin and yang. From liang yi, the "four elements" (si xiang), were derived: earth, wind, fire and water. The four elements can also be interpreted as the four directions, four seasons, etc. From the four elements, the “eight trigrams” (ba gua) were derived, which were then used to form the “sixty-four trigrams.” These 64 trigrams (64 gua) are used to represent everything in the universe and are frequently used for fortelling the future or fortune-telling.
In essence, tai chi was the beginning of the universe, giving birth to everything in it. It represents the order or tao of the universe and means “supreme,” “infinite,” “absolute,” “one and only.”