Now we're gonna discuss the basic theory behind chi sau. Now, chi sau is one of the most famous exercises we have in Wing Chun. Chi sau means "sticking hands" or can also be translated as clinging arms and the idea is that when we have contact with our opponent's arms, or in this case, your partner's arms in training, you wanna learn to feel the direction and force of the attack so that you can unload the force, abandon the force, and basically make use of what your opponent is doing based on what's going on that moment.
Chi sau is not based on preset routines. We start by teaching routines so that the student can learn some basic movements and then the idea is that it eventually frees up a little bit. So, we have a saying in Wing Chun. We say, "Yau sau chi sau, mo sau joi ying," which means, if there are hands in front of you, stick to them; if there are no hands in front of you, go to your opponent's body.
So the purpose of chi sau, is in fact, not to stick to your opponents arms for the sake of sticking to your opponents arms. What we wanna do is we wanna step in and knock out our opponent. But if we run into our opponents arms, then we can make use of the force. I believe Jessie Glover said it best. He was Bruce Lee's first student in the US. He said, "Chi sau is back up for your punching, not the other way around." So our primary focus is to go in and hit; it's not to go in and do chi sau.
So here, we see two students practicing chi sau together. And the idea is to stick, and to feel, and to practice according to what's going on. And whether one person gets hit or not is actually not the issue. The idea is just to feel what's going on and actually get used to getting hit and borrowing force and giving it away.