Although the concept of a Centerline is not unique to Wing Chun Gung Fu, it is visualized and applied in no other martial arts system in the same way. Aside from the Centerline, the Wing Chun man employs pyramidal, circular, angular, and linear structures to defeat opponents through scientific technique rather than brute strength or speed. Proper use of the Centerline, also known as Seen Wai Miu Yoang in Cantonese, heavily relies on correct Self-Structure and, in turn, adequate application of that structure to that of the opponent. The “Concept of Reference” refers to this combination of form and combat application. Wai Jee, or reference, is similar to target shooting in that it requires setting the sights of a rifle to pinpoint accuracy and then aiming that rifle with equal precision. The Self-Structure (the gun sight) and the Applied Structure (the marksman’s aim) should be as accurate as possible. If either element is incorrect, the execution will be subpar and may fail. However, suppose the Wing Chun practitioner’s technique is correctly structured in terms of reference. In that case, he can combine power, focus, and positioning to maximize the effectiveness of the method at hand.
Yin and Yang Motion—The Yin and Yang principles determine the reference and, thus, the application of a technique. To fully understand how this concept works, the reader must first understand the Centerline Theory and The Cutting Angle, which have already been discussed. He must also be familiar with the concepts of Yin and Yang, as well as “The Arc of Power,” which will be discussed further below. Most people are ordinary with the Yin/Yang symbol. However, one must first become acquainted with certain aspects of Chinese philosophy to comprehend its significance.
The symbol itself is a perfect circle divided into two equal but seemingly opposing halves that can represent anything from night and day, male and female, life and death. One half is black (Yin), meaning everything in nature that is negative, passive, feminine, or receiving. The white (Yang) half represents that which is positive, aggressive, masculine, or forceful. And within each half, a small circular section is the opposite color. The contrasting colors represent the two ends of a full spectrum. And the fact that each contains a little bit of the other is meant to convey the idea that nothing can be challenging or it will snap due to brittleness. Nothing can be utterly soft because it would fall apart. However, there is an innate Yin/Yang balance in all things in nature, and it is usually apparent which quality is more prevalent. While we categorize motions as Yin or Yang in nature in Wing Chun Gung Fu, we also strive to incorporate some qualities of both into every movement.
“Soft” vs. “Hard”—Just as everything in nature, from the smallest grain of sand to the highest mountain and beyond, can be analyzed in terms of Yin/Yang balance, the same concept of equal, opposing, yet complementary forces applies equally to the Wing Chun system’s many attacking and defending motions. This leads to the belief of “Yin and Yang Motions.” Yang or “Positive” activities catch the momentum of the torque on the side of the forward-moving shoulder and use its centrifugal force (the power of a spinning circle to throw objects off its surface) to push or impact the opponent. Yin or “Negative” motions on the retracting side that capitalize on centripetal force (the power of a spinning circle to draw inward as a whirlpool) have the opposite effect on the rival, pulling him in or “borrowing power” as they latch on to the “returning” power of the Power Arc.
One of the factors that Complex Motions are structurally attainable in Wing Chun is because of the Yin and Yang distribution of torquing power. As long as the student merges Yin and Yang motions on their correlating sides, he can perform a wide range of Complex Blocks, Attacks, and Double Motions, all of which rely on single pivots to power multiple simultaneous hands/or leg techniques.