By Greg LeBlanc
The function of the Chi Sau drill is to build automatic reactions at close range. In the application of Wing Chun the advancing attacker is met using the primary preemptive tactic called Jeet. If your attack becomes obstructed, Chi Sau skills take over. The drill is training us to skillfully react from being tangled up. In thinking about what we are preparing for, the attacker on the street is not going to hit in a predictable manner, but will be a moving target either to you or moving away from you, may very likely land hits on you, and will be hitting in combinations (skilled or wild). If Chi Sau trains us for something else than the above, then that training becomes more about the drill and less about what the drill is preparing us for. Meaning it is possible to become very skilled at the Chi Sau game, but only under conditions that take place in the drill itself (sometimes called the Chi Sau bubble). Chi Sau is a drill intended for training at the elbow range (where an obstruction takes place), if we break the distance of the drill (leaving the elbow range) then we have effectively ended the drill.
If we step out the the Chi Sau/Gwoh Sau drill we are now are playing at San Sau range (distance fighting range); this distinction is something I try and make very clear when I am coaching. The application being, if someone wants to Chi Sau/Gwoh Sau but then jumps out of the elbow range, I know that the play has now switched to San Sau. One option I employ for clarification is to use the Predator Armor, which allows for a safe way to test the above statements. To see if in fact a live attacker can be intercepted (regardless of the types of attack), hit with accurate and full power punches, skillfully using assistant hands as needed and all done in a way that doesn't easily allow for retreat or the trading of punches. If Wing Chun doesn't meet an attack with an intercepting attack, if it doesn't take position and control centerline; what then is the meaning of the Chi Sau drill? In other words Chi Sau as the soul of the system is outlining and defining the way Wing Chun was designed to be used. If we are not taking position and attacking the attack, but instead are moving in and out (stepping back), how does Wing Chun then differ from any other punching system?