One of my favorite zen books is Only Don’t Know, The Teaching Letter of Zen Master Seung Sahn. He talks about primary point. I have tried to explain this idea to others, however, his words explain it best:

“I often talk about primary point. What is primary point? If you have a scale with nothing on it, the indicator points to zero. When you put something on the scale, the pointer swings to read the weight. When you remove the weight, the pointer returns to zero. This is the primary point. After you find your primary point, then good feelings may come or bad feelings may come, so your pointer swings in one direction or the other, but this doesn’t matter. When the feeling is over, the pointer will swing back to zero.

But if you haven’t found your primary point, then it is like taking a heavy object off the scale with the pointer still indicating 10 pounds, or only returning part of the way back towards zero. Then you have a problem. Your scale does not weigh accurately. If you put another heavy object on it, it might break completely.

So first you must find your primary point. Then you must keep it strong. A taxi has weak shock absorbers, so it bounces up and down when it hits a small bump. A train has strong shock absorbers, so it is very steady. If you keep your primary point, your mind-spring will become stronger and stronger. A big problem will come and your mind will move, but it will soon return to primary point. Finally your mind will be very strong, and it will be able to carry any load.”