"Chan si jing" or silk reeling force is a circular and spiral force. When we practice Chen style Taijiquan, we can see or feel that our legs, body and arms are turning or twisting on their own axis upwards and downwards, sending our internal force from the feet to the arms and out. This also happens in a push-hands situation. For example, when we are pushed, we bend our back knee and turn our waist, and our weight sinks to transfer the incoming force sideways and downwards. When we push, our back leg straightens up and the spiral force goes upwards and forwards.
Power discharge in a routine looks like a punch, a palm or elbow strike, a kick, etc. in the external systems. The difference is in its execution: we are still very relaxed, hit hard only at the point of contact, and then relaxed again - a very economical and efficient way of using our energy as we can send all our strength out on to the recipient. The impact of this kind of power discharge can cause injury to our opponent.
As Chan si jing is always present in the Taiji form (push-hands and even sparring), it can be said that practicing Taijiquan is practicing Chan si jing. Our arms and legs keep turning in big or small circles. They look soft but the upright body helps to make them strong. This power is internal force. The more you practice, the stronger your internal force will be. It is the force of the whole body.
Chan si jing originates from dantian and is executed through the waist and the chest with the help of our hips and legs. It is important that we train until the chest and the waist are united into one piece in our movements. (We should always line up our shoulders and our hips from the top down and make them work together as one unit with the waist in control. We should avoid moving the shoulders only. If we consider that our torso from the shoulders down to the hips is one piece, this will certainly help.) Then we can use our chest and waist (torso) to power our arms, which will move in spiral and circular movements. The execution of Chan si jing is through turning our chest and waist -- left or right, but not forwards and backwards (which can reduce the force produced) to propel our arms. Our torso (chest and waist) controls not only our arms but also our legs. When we turn left or right, our legs will have to turn in the same direction to give their support. That way the whole body force is produced. We should not turn or move our arms by themselves.
Quite a few Chan si jing exercises have been invented by some practitioners. They are not bad, but I do not practice or teach them. I only teach two "chan si jing" exercises: these are the moves used in single and two-hand push-hands. I show my students what is Peng (ward-off), Lu (roll-back) and An (push), and ask them to practice at home. This is just like one person push-hands movements. The more they practice, the better they will be at push-hands.
Basically, there are two kinds of "chan si jing." "Shun chan" means "twining out or twining smoothly;" in other words, turn the arms and legs outwards. (Right arms and right legs turn right; and left arms and left legs turn left.) "Ni chan" means "twining in or twining adversely." We turn our arms and legs inwards. That is to say right arm and right leg turn left; and left arm and left leg turn right.
Besides rotating on their axis, our arms and hands keep drawing circles when we practice Taijiquan. Our hands can move up or down. Then we have up or down "chan si jing". When our arms or hands move to the left, we have the left "chan si jing;" to the right, the right "chan si jing." Similarly, we have big or small "chan si jing," front or back "chan si jing," inside or outside "chan si jing." These five different kinds of "chan si jing" - up/down, left/right, front/back, big/small and inside/outside - are classified according to the position where the hands are; while the two basic "chan si jing" - shun chan and ni chan - are classified according to the way the body, arms and legs rotate on their own axis. When we talk of "chan si jing," we normally refer to the latter.
When we practice the routine, chan si jing can help our form get smoother, rounder and so our movements are continuous and not broken. This is achieved through two stages. At the early stage it is important that we practice the routine very gently, which can nurture our qi or life energy, and make us strong. At this stage, our qi is activated by the movements of the routine, and is present mainly in the movements themselves, which we call "outside circle". Later on our qi gets stronger and stronger, and it no longer needs the movements to activate its flow. Instead, our qi drives our movements. If we have the correct body alignment and move in a spiral and circular manner it is a lot easier for our qi to drive our moves. Now our qi moves in the "inner circle" and will develop into "Jing" meaning internal force. This is what people who practice Taijiquan for self-defence will aim for. We still need to be relaxed and always use our torso to spin our arms and legs. There is a big difference in the degree of the internal force when we have the chan si jing and without chan si jing.
In self-defence, the twining of the whole body on its axis (shun chan and ni chan), and the circular movements (the five pairs of positional chan si jing) help to deflect punches, pushes, kicks, etc. more efficiently. The force that comes in contact with our arms or body is partly diverted to one side and the ground and partly dispersed through the whole body, making the impact on us minimal.
Fa-jing or issuing power is an explosive expression of chan si jing. The power produced by twining up the whole body is stronger than that produced by using only the arm. At its highest level, a good Taiji practitioner can use chan si jing to deflect and attack at the same time. It is said such masters like Chen Fa-ke and Hong Jun-sheng when attacked could send the attacker many meters away at just one block.
Before I conclude, I would like to answer the question how we can move forward and backward by turning our waist. We do so by changing our stance. For example, when we want to push we turn left (or right) and change from a reverse bow stance to a bow stance. That way our body will move forward but without losing the peng energy. When we neutralize a push, like doing a roll-back, we turn and change to a reverse bow stance. Then our body will move backward. (To be more exact, one part of the body moves backward while the other forward.) If we retreat instead of turning to neutralize we will lose the peng energy and so can be thrown off balance very easily. This should be worked out from push-hands to gain the experience. (My students know this very well and never have doubt on this.) In short, if we turn our waist we can move forward or backward with spiral move and strong internal power. But if we move forward or backward to do a move we will lose the internal strength as the spiral movement disappears.
