I'm a Doctor, atleast I play one on the internets.
Principals are incharge of schools. Generally the main person or sometimes the main thing in some process.
Principle is a type of concept or theory. Most people confuse "principal" with "concept" and call the main theory components principles.
In Wing Tsun we say that Principles are not stand alone theorys but a group of concepts that work together to make a system. Concepts are the stand alone theorys that are more universal.
"Always go forward" is a WT principle that only works in conjunction with sticking, yeilding, and following. This makes a system that we use, they do not stand alone.
"Balance" is a Latosa Escrima Concept that applies to all MA and contains the above system of principles. It can be used as a stand alone theory.
"If anything is gained from this, it should be you both wanting to get better so you can make up for how crappy you are now." KidSpatula about the Sirc vs DTT Gong Sau Event
Until the Bulltube is fixed:
DTT vs Sirc
Single Sign On provided by vBSSO