It is a common mistake for new students to regard taijiquan as 'fighting'. This is a misconception that reflects a conflict-based, competitive mentality. Our training is designed to cure people of their aggression.
In self defence, we have no desire whatsoever to fight. Fighting is when you stand in front of someone and trade blows with them. It is a struggle. Struggling occurs when you try to impose your will and encounter resistance.
In taijiquan, we wish to evade and depart - not struggle.
A taijiquan student merges with the incoming attack and does not fight the assailant. Our skill lies with allowing the assailant to move as he pleases, without blocking the line of force. We redirect that force, and borrow its power for our counter.
There is no fight. A fighter tires himself by contesting the incoming force. This is not the way.