Zhang Guo's Law of Faith was created by Zhang Guo, a famous Taoist in the Tang Dynasty, and Zhang Guo was Zhang Lao Guo in the legendary Eight Immortals. This method is also a kind of static work of breathing and practicing breathing. It was first published in Volume 59 of Seven Trillions of Yun Qi, which was one of the popular methods in Tang and Song Dynasties. It is characterized by gradually prolonging the time of being trapped in the body as a means to finally reach the state of "fetal interest", which is actually a replica of the "holding the baby's fetal interest method"

The specific training method is: supine posture, fists on both sides of legs, so as to converge the mind and abandon all kinds of distractions. Inhale slowly through your nose, hold your breath when you are full, and count from one to more than one hundred in your mind. It is difficult to hold your breath, you can loosen it a little, then close it immediately after inhaling until your feet sweat, and then slowly spit out the closed breath, but you must inhale and exhale very slightly, so that you can't see the breath. With the deepening of kung fu, the number of silent breaths is gradually extended. Usually, if you can hold your breath to l000-2000 every time, you don't have to eat whole grains, and you can naturally have a "fetal interest" state during this period. If you can silently count to 5000 at a time, you can reach the realm of Excellence.