Emptying the abdomen with qi is an effort to accumulate internal qi and become internal strength. The ancients believed that the abdomen was an important part of nourishing the whole body. There is a saying: "without fire, you can warm your whole body;" Without water, it can nourish the five internal organs, which is related to the life of the whole body. If this is endless, life will not die. " This was originally a Taoist saying. So in ancient times, all fighters took Shen Dantian as their basic skill.