Tai chi (Taiji) chuan is an internal Chinese martial art whose theory agrees with the principles of Chinese philosophy and Taoism in particular. As the name tai chi chuan was from the Taiji symbol (taijitu, yin-yang diagram), tai chi chuan is said to be a study of Yin and Yang (Two opposing but complementary forces whose interaction and balance affect everything in the universe) principles in the Tao Te Ching (《道德经》, Dàodé Jīng).

Tai chi chuan is classified as a form of traditional Chinese martial arts of the Neijia (soft or internal) branch. It is practiced in a low speed and is considered a soft style martial art applied with internal power, focusing the mind solely on the movements of the form which helps to bring about a state of mental calm and clarity. Tai chi chuan teachers often wear loose, comfortable clothing and flat-soled shoes.

Today, tai chi has spread worldwide. Some of Tai chi chuan's training forms are well known to westerners as the slow motion routines that groups of people practice together every morning in parks around the world, particularly in China.