Martial arts drills that set Wing Tsun kung-fu apart from others include chi sau. Chi sau is a drill that often becomes a form of sparring. Some other Chinese martial arts have a tradition of a clinging arms drill like Wing Tsun’s chi sau but not as thorough in its focus.
Chi sau is also referred to as ‘sticky hands.’ This reference is because the idea of ‘sticking’ or ‘clinging’ to an attacker’s arms gives the defender the information needed to defend such as the strength of the attack, the direction, the momentum, and the reality of the attack. Without sticking there is the risk of mischaracterizing a threat by seeing an attack coming which can be deceptive.