Energy path is the pathway that energy travels on. There are both a physical path and a virtual path for a given setup. For any three points in the body, they can form a triangle (unless they all fall into one straight line). For this discussion, let's use right hand, left kua and left foot as the three points. As similarly discussed in this previous article, while the right hand and left kua form one physical (solid) line, and the left kua and left foot form another physical (solid) line, the right hand and left foot form a virtual (invisible) line. While the actual energy travels along the two physical lines, it can be viewed as if it travels on the virtual line.
Consider a case when the opponent touches me with his right hand with the setup as described above, the virtual line represent the energy path. If I can match the power, angle and speed as presented by the energy path, it can be viewed as a non-moving rod. In Practical Method, we may consider it as the base dimension and let's call it "one". Based on the principle of yin-yang separation, we want to add an action in the another dimension, which we call "two". This approach of establishing actions is often referred as "Add One". When the 2nd action is applied, it must not influence/affect/disrupt/impact the first action, in other words, it is totally independent of the first action. In order to use the 2nd action to create a rotation based on the fixed rod (like a rotisserie), the first action must be responsible for keeping the rod in place (non-moving) while the 2nd action needs to go over or under the rod, or both at the same time, i.e. the 2nd action creates another energy path that goes around the rod.
In actual operation, if the opponent pushes on me, I would first bring that energy to my rear foot. This creates one energy path in his body, and one energy path through my body to the ground. This establishes "one". Note that this is no push back to the opponent, I only attempt to adjust my body parts to redirect the incoming energy to the ground. This is like collecting water through a funnel, and let it out the other end. Another point about the establishing the first energy path is that I must get to a point that I am stuck, which is uncomfortable. In order to truly do a 2nd action ("two"), I must be able to stretch in a way that does not alter/disrupt the first energy path.
As described above, I match the opponent by meeting his power at our fronts, and that location becomes a non-moving point. Another way is to let the opponent's force be matched by a stretch that I create against a designated non-moving point of my own. A third way to match is to create an equal and opposite action against the opponent, in between his action and mine, there is a non-moving point. In all 3 examples, there is always a non-moving point, only with which rotation is possible. However, rotation is only a result, we only perform linear actions against restrictions to create stretches. Another point to note is that the 1st and 2nd energy paths must cross each other but without affecting each other to create an effect that is larger than the sum of them. Within a given energy path, there is also a non-moving dot. If we can disrupt/move the non-moving point of the opponent's energy path, the opponent's power won't be able to continue.
The way we use power produces one energy path, but in Practical Method, the indirect or resultant energy path is what we really want to use. Once we have one level of indirectness, we will realize that it is possible to have more levels. What it means is, for example, if action B causes action A, it is possible to create two levels of indirectness by having action C to cause action B, which, in turns, causes action A. The better we become, the more indirect our actions will be. The opponent will have a difficult time stopping us because he can't identify the real source of power when he can only feel the effect of it.
Sorting out the energy paths is like combing through the hair to remove any knots. Once we see them and can keep them in place, we will also see the space in between, which we will ultimately need take up.
The above summarizes my understanding at this point of time. Understanding will increase as our abilities increase. We must keep our consistent training to strive for further breakthroughs. Happy Training!