8 basic principles of Chi Sao.

 1. Safety first.
First, you have to think about protecting yourself and not thinking about attacking. Self-defense The most important is to be unharmed/safe.  

2. Keep your distances & positions
 Angles & positions of the arms, positions of the body, horse etc ... Shoulder facing shoulder. Protect his center and control that of our opponent. Do not move too much...  

3. Keep your hands glued
The best is sticking hands - It is from the contact that our Kung Fu can express itself - If we lose contact, we must seek to find it by "calling" the hands of the opponent [Wen Sao ]. From the contact, think to keep a constant push forward in order to favor "listening to movements".  

4. Relax & No power 
From a physical point of view: Muscle relaxation - avoid high muscular tension                                                        Developing techniques without focusing on strength
From a mental point of view: Staying calm & controlling your emotions *  

5. Using the feeling
Feel the movements of our opponent - avoid thinking or thinking before acting * Trusting our feeling will encourage spontaneous reactions and reflexes.  

6. Timing
The right time to defend or attack in action - appropriate reaction speed etc ... A good feeling will improve your timing.  

7. Do not rush Perform the techniques one by one and correctly [Complete each movement]. Act in action without precipitation and without panic.  

8. Take a chance when it comes
When the opportunity presents itself and you are not exposed to a counter [To Da] - then you can attack .
In Wing Chun, attack must not be "calculated" premeditated or even desired, it must come naturally and spontaneously according to the errors of our adversary.   * Benefit of Meditation and Work on Self