In 1934 I was in Changsha pushing hands with a classmate. Wang Ruen was watching from the side. Suddenly he said, “How is it that there is no opening or closing in your push-hands?” I quickly stopped and asked, “When you taught me push-hands you never spoke of opening and closing. Teach us, where should we look for this opening and closing?” He said, “Don’t the Boxing Treatises say that if you can open and close, then you can breathe, and if you can breathe then you will be spirited and lively? You should have discovered this principle yourself.” I said, “A long time ago I suspected that I didn’t really comprehend those two words. What is the meaning of “if you can open and close, then you can breathe”? Being unable to breathe, isn’t that the same as being dead?”
...Master Wang continued, “When you first began to study, I couldn’t speak of this kind of movement, because it is too complicated. It is not easy to feel and comprehend. But at this stage in your training, you must devote your effort to synchronizing opening and closing with the breath.” He then proceeded to point out some examples from the form. For instance, ward-off and press are “opening”. Roll-back and push are “closing”.
From that time on, I began to search for opening and closing movements whenever I practiced the form. After several days I thought I had gotten it. I practiced “Grasp the Sparrow’s Tail” while Master Wang observed. Master Wang said with a laugh, “No need to continue. Your opening is not opening; your closing is not closing.” At that time, he had a folding fan in his hand. As he waved the fan, flicking it open and closed, he asked, “How is this opening and closing produced?” I said, “It is produced by the motion of your hand.” He shook his head and pointed to the button that held the ribs of the fan together, saying, “Only if you have this thing is it possible to open and close.” Then he pointed to the door of the house, saying, “It is just like this door–which must have a hinge in order to open and close. You haven’t yet discovered this pivot, so naturally your opening is not opening, your closing is not closing.” I asked, “Where is the pivot?” He replied, “This is something you yourself must find. If I tell you, it would be of no use.”
From
https://neigong.net/2007/08/12/a-study- ... ush-hands/