Feeling your Weight
Although we start with our stance square and our weight even on both legs, it does not mean we cannot step with one foot forwards and the other one backwards. For example, if we want to use Gaau Cha Sau交叉手to trap our opponent’s hands we need to step forwards in order to make his hands closer to his body so he cannot move. Then we can hit him. This is the reason for stepping forwards in Chi Sau 黐手. If you step forwards for no reason, then you give your opponent a chance to Laap Sau 擸手 and your hand on the same side you have stepped forward with. This is because in a way you are already leaning forwards and so it is easy to pull that side and this makes it hard to defend against. Once we pull their hand, their back will be exposed and that will allow us to hit or push them to make them lose their balance even more.
A high level Wing Chun person can feel where their opponent’s weight is and then use this situation to their advantage. That is why in traditional Wing Chun we do not step forwards in the beginning when we Chi Sau and then the more we practise, and then we can feel our opponent’s weight and energy.