Wing Chun is a very logical and sensible gung-fu system that was scientifically designed for and based on the motions of the human body. Elements of geometry, physics, physiology and philosophy are the foundation on which Ng Mui and Yim Wing Chun built the ultra-effective and economical system of close range combat practiced today.

Many intricate concepts and principles govern the method in which its techniques are applied instinctively by a skilled fighter. But of all those concepts and principles that make the system unique, there is one which is so fundamental to Wing Chun fighting strategy that it can be called the "Backbone of The System." Known as the "Centerline Theory" (Joong Seen Lay), it involves the recognition, usage and manipulation of an imaginary line or plane that connects two fighters and the relationship of that line or plane to various lines and angles of attack and defense.

As the Centerline Theory is strongly rooted in geometry, the motions and postures of two fighters are referred to in terms of lines, triangles, pyramids and angles rather than as stances, punches and kicks. Thus, it becomes necessary that the Wing Chun student be able to visualize them as such —- in effect depersonalizing the opponent, himself and the blocking and/or attacking motions used by both during combat, allowing all elements to be viewed in a clinical light. This ability to remain emotionally detached in combat is developed through many hours of intense practice on Sticky Hands, sparring and drills, all of which accustom the student to dealing with relentless attack pressure while remaining cool under fire. While in the initial stages of training, the student might flinch or panic when under attack, he will soon begin to view oncoming kicks and punches as routine everyday occurrences —- more fodder for the practice of technique than serious threat. At this point, the student can begin to see the lines, angles and pyramids created by both fighters and their implications on his own structure.

This emotional detachment allows him to put the Centerline Theory into practice. The Wing Chun fighter must learn to remain calm and to relax the mind, even in the midst of all out combat, to eliminate the negative effects of tension, fear or anger, which can handle the effective utilization of Centerline strategy.

Although at first the Centerline Theory may seem quite complex and even a bit too confusing to apply in an actual combat situation, in time the Wing Chun student will find that once the core concept is grasped, use of Centerline strategy becomes more and more natural. In other words, the student will begin to apply the Centerline Theory instinctively in conjunction with other key concepts and principles of the system ever devised.

Major Components

The major components of the Centerline Theory, aside from the Centerline itself, are: "Motherline," the "Self-Centerline," the "Centerline Plane," the "Horizontal Elbow Level Motherline, "Attack and Defense Pyramids," the "Cutting Angle," "Centerline Advantage," and "Facing," as well as the concepts of "Inside Centerline" and Giu Sau.

The following is an individual analysis of each.

Jik See: The Vertical Motherline.

The "Motherline." Called the Jick Joong or the Jick Seen in Chinese, the Motherline is an imaginary vertical line which passes through the middle/top of the head and goes down through the center of the body to the floor in such a way that it forms an axis of rotation for the body. When a person pivots on their axis, the Motherline does not change. But if the person takes a step in any direction, the Motherline shifts accordingly.

The Self-Centerline.

The "Self-Centerline." The Self-Centerline can be defined as the vertical line that divides the body into two equal halves. When there is no opponent, the Self-Centerline passes down the middle/ front and rear of the head and body, as if it were painted on. It can be used during forms practice as a reference point for correct elbow and/or hand position during technique execution. Certain blocks' structures dictate that the elbow, wrist or other part of the hand falls on the Self-Centerline, while certain attack structures call for the knuckles, palm heel, elbow point or other area to be central. For example, when executing the Tan Sau motion in Siu Leem Tau, the middle finger should point 45 degrees inward toward the Self-Centerline from the origin of the motion until it reaches that line and continues to follow it as the elbow is drawn in that both the middle finger and the inner elbow end up on the Self-Centerline in the fully extended Tan Sau position.