The theory is that Chang San-feng originated a style that combined both existing combat techniques and other movements, primarily designed to increase the flow of chi energy through the body, thus creating a form that was a physical manifestation of Taoist thinking.

Going back even further, the ancestors of tai chi can be seen in the sixth century: Bodhidharma visited the Shao-lin monastery, and developed a system of excersise for the monks, who he saw in poor physical condition from too much meditation. This was known as the Eighteen Form Lohan Excersise. Later, in the eighth century, this was developed into a 37-form 'Long Kung-Fu', which unlike other schools of Kung-fu, was based upon a 'soft' or internal approach, rather than a 'hard' external one.

Looking back even further than this, we can see that in the third century, the physician Hua-tu'o created a system of excersise to aid digestion and circulation, based upon the movements of animals and birds. The effect of this system was to move every part of the body.

Tai Chi Chuan, the original combat form of Tai Chi, translated means Supreme Ultimate Fist, 'chuan' meaning a method of boxing or combat. Unlike many other martial arts, which were 'aggressive' or outward, Tai Chi Chuan's main principle was that of a 'soft' combat - absorbing the opponent's aggressive energy and using it against him. This is a principle of yin and yang, a balance of opposites where soft is used to overcome hard: the maxim "four ounces to deflect a thousand pounds" or "overcome a weight of a thousand carries by four ounces" is often used. Imagine an opponent twice your weight throwing a powerful punch - the Tai Chi Chuan adept would step back, absorb the punch by grasping the fist and pulling it past him, using his opponent's own forward energy and motion to overbalance the attacker. Or he might respond in any number of ways, always using the same principles.

Although 'soft', this was a very violent form, designed for killing and maiming (lest we forget), in an efficient and scientific way. Modern non-violent tai chi as a form on its own, rather than being a part of chuan, was developed much later, as the need for combat gradually decreased - although the tai chi practitioner is always aware that the forms that he is using are the same as those of combat, but slower. In the eighteenth century, Yang Lu-chan removed the label of 'secrecy' on the form, and started his own 'Yang' style of tai chi, becoming known at the imperial court as 'Yang the Unsurpassable'. After his death, one of his students, Chen Hsui-feng, became head of the Yang School. One of Yang Lu-chan's sons, Yang Pan-hou, had a student called Wu Quan-yu, whose son; Wu Chien-chuan became disillusioned with the Yang style and created his own 'Wu' style.

Another of Yang Lu-chan's sons, Yang Chien-hou, had three sons, one of which, Yang Chen-fu, is largely responsible for popularising the Yang style and bringing it to the West in this century. He became known as 'Yang the Invincible'