One of Sifu’s signatures is “no force” (not “Empty Force”, i.e. bouncing people without touching them) but yielding without force, and even when expressing force (Fajin 發勁) the force seems to come in as a wave, not as a focused point.
This yielding with no force is contrary to what I learned before. When first doing that, a common mistake – which I myself made plenty of, is trying too hard to be soft and yielding. It’s not based on true Song (non-collapsed relaxing 鬆). The first step is to train the sensitivity of you skin and learn to Song. Once I started to get past that hurdle, then the problem became that my yielding just wasn’t that great, and people who used force would easily trapped me.
There is no magic. Sifu said “everything is in the form” – mobilize with Qi, learn to move the joints, and harmonize external and internal. On one side, your arm has a wrist joint, elbow and shoulder joints. Beyond the arm, you have hip, knee, foot joints. If they trap you on one side, you have the other side. The Classics says “Stick, adhere, link, and follow”. Yielding then is just the understanding “in your body” of these core concepts and principles, plus the principle of Zhong Ding 中定.
We can say that this is the Yin side of Tai Chi.