Tai Chi Chuan (simplified Chinese: 太极拳; traditional Chinese: 太極拳; pinyin: tàijíquán) is an internal Chinese martial art often practiced for health reasons. Most modern styles of tai chi trace their development to at least one of the five traditional schools: Chen (陳氏), Yang (楊氏), Wu/Hao (武氏), Wu (吳氏) and Sun (孫氏).

The term t'ai chi ch'uan literally translates as "supreme ultimate fist", "boundless fist", "great extremes boxing", or simply "the ultimate". The concept of the Taiji ("supreme ultimate") appears in both Taoist and Confucian Chinese philosophy, where it represents the fusion or mother of Yin and Yang into a single Ultimate of wuji (無極) state. Please note the Chinese word for "Chi" in Tai Chi / Taiji is different than the "Chi" in Chi Kung / Qigong (氣功). Chi Kung is any system of "energy cultivation".

The philosophy of Tai Chi Chuan is that if one uses hardness to resist violent force, then both sides are certain to be injured at least to some degree. Such injury, according to tai chi theory, is a natural consequence of meeting brute force with brute force. Instead, students are taught not to directly fight or resist an incoming force, but to meet it in softness and follow its motion while remaining in physical contact until the incoming force of attack exhausts itself or can be safely redirected, meeting yang with yin. Done correctly, this yin/yang or yang/yin balance in combat, or in a broader philosophical sense, is a primary goal of Tai Chi Chuan training. Lao Tzu stated this in the Tao Te Ching, "The soft and the pliable will defeat the hard and strong."