Internal Chinese martial art practiced for both its defense training and its health benefits. Though originally conceived as a martial art, it is also typically practiced for a variety of other personal reasons: competitive wrestling in the format of pushing hands (tui shou), demonstration competitions, and achieving greater longevity. As a result, a multitude of training forms exist, both traditional and modern, which correspond to those aims with differing emphasis. Some training forms of t'ai chi ch'uan are especially known for being practiced with relatively slow movements.

Chen Family Taijiquan (陳氏太極拳) is the mother form of Taijiquan from which other various styles such as Yang, Wu and Sun ultimately derive. 
The Taijiquan creator, Chen Wangting, was a 9th generation representative of the Chen family about 400 years ago (in the late Ming dynasty). He created Taijiquan based upon the Yin and Yang theory from the Yijing (易經: yìjīng), breathing of Qi Inducing Practice (導引吐納: dǎoyǐntǔnà), 29 postures of the military tactics book (紀效新書: jìxiàoxīnshū) by Qi Jiguang (戚繼光: Qī Jìgūang), and the theory of meridians in Chinese medicine. 
Chen Family Taijiquan requires sturdiness, softness, fastness and slowness. If there is only slowness,  all the principles of Taijiquan cannot be captured.