Part the Wild Horse's Mane (左右野马分鬃 Zuoyou Yémǎ Fēnzōng), is a common posture found in most forms of t'ai chi ch'uan. Typically performed from Gong Bu stance, mantains the forward hand at shoulder height while the backward hand remains at waist height.
Part the Wild Horse's Mane is one of the first movements/postures learned by the beginers since it displays many important lessons, such as fluidity and correct alignement.
The Movement follows the Lieh (Splitting) and Zhou Pu (Left Step), followed by a You Pu (Right Step) techniques.
This posture is meant to train reflexes to grab the opponents arm whether to lock his arm or to destabilize him (the forward arm goes under the opponent's arm, while the rear arm grabs the opponent's wrist).