WING CHUN: THE SKILL OF RETURNING ENERGY.
On first sight of the Chum Kiu Form (2nd form), one will notice that the practitioner spends a considerable amount of time turning on the spot. Indeed, the Chuen Ma, or Turning Stance, is another unique and vital element in the Wing Chun Kung Fu system. Normally, Chuen Ma is applied in response to an attacker pressing in towards the fighter's Centre Line. The effect is that the attacker is deflected to the side. As a rule Chuen Ma should not be used unless the attacker is pressing into the Centre Line. This can be illustrated by observing the rotation of the trunk of the body. As the waist turns, the entire upper body turns as a result. The effect is such that the momentum that derives from the turn in the body drives the strikes and blocks of Wing Chun.
Although, Chuen Ma could be applied prior to the assailant's attack with other forms of footwork such as Sam-Kok-Ma or Sik-Ma or Chong Ma to move triangularly towards the opponent to avoid excessively powerful force that results from the size of the attacker. Chuen Ma stance is subtle, allowing the Wing Chun fighter to turn only as much as necessary or required by the force of the attacker. Note, Chuen Ma is a transient fighting stance, as a rule the Wing Chun practitioner will always quickly re-establish a forward fighting stance in order to dominate the Centre Line.
The 2nd form reinforces the concept that shapes and structures gained from the First Form (Sui Nim Tao) should never be compromised, hence the combination of turning the frame under pressure. The effect is that a Wing Chun practitioner never allows their blocking arm to be compressed or crushed into their body as you turn. Indeed, there is always forward energy within the shapes and is maintained under pressure with the reliance of the turning stance.