In southern China I have been told by the Kwok Fu Association that the Leung Bik System is known around China as the "True Attack Fighting System" of Wing Chun.
Traditional Wing Chun's Central Line concept has Six Gates to defend.
Upper Gate, Left and Right.
Middle Gate, Left and Right.
Lower Gate, Left and Right.
A Perpetrator can attack the upper gate, middle gate and lower gate, left side or right sight, which comprises the six gates to defend.
Traditional Wing Chun's Center Line is an axis down the center of the body dividing it into symmetry.
Another idea of Center Line is; the body is divided into a vertical and horizontal line and where they intersect is the Center Line.
The shortest distance between two points is a straight line, therefore, from a point on the defender's center line to a point on the attacker's center line, in a straight line, constitutes the shortest distance, allowing for the quickest path of Attack.
The Central Line is the area in front of a person that one must defend which comprises the six gates.
When one faces the point of contact, the arms become equal length which allows a person to attack and defend simultaneously.
In essence the defender has 2 center lines. One from his center to the point of contact and one from his center to the opponents center.
The Central line principles are unique to the Leung Bik / Yip Man Wing Chun System.
Travelling around China since 2006, I have seen a lot of Wing Chun practitioners use simultaneous attack and defence but they do not turn a face the point of contact as much as Leung Bik System, therefore exposing their Flanks, much more.
Pien Sun Kulo Wing Chun also profoundly face the point of contact.
Traditional Wing Chun was created by Leung Jan's Son, Leung Bik.
I suppose it is only natural the two wing chun systems share some core principles.
Core Principles Kulao Wing Chun and Traditional Wing Chun Systems Share:
Parallel Leg / Arm fighting and self defence.
Side Neutral Stance as a starting point (neutral stance with both feet facing at a 45 degree angle or more.
A great emphasis on using Lap Sao as a form of control.
More emphasis on China and Dim Mak and not much reliance on Chain Punching.
Traditional Wing Chun derives from the Leung Bik / Yip Man Wing Chun System.
Yip Man learnt this style of Wing Chun from Leung Bik in Hong Kong around 1917.
Leung Bik is the Son of the legendary "king fo wing chun", Dr. Leung Jan.
This unique wing chun fighting system is relatively new in Australia, being introduced to Melbourne in the late 70's, by Grand Master William Cheung.
Jee Shin Wing Chun Links: