Before Guiguzi’s master passed away, he gave Guiguzi a bamboo slip on which was written the word “heavenly book”: What kind of heavenly book did master Guiguzi leave for him? . Gui Guzi opened it and found that there was not a single word in the book from beginning to end. Gui Guzi was puzzled. He thought hard for a while, but couldn't come up with a result. He felt helpless and empty in his heart, and he had no intention of tea or food, so he got into his cave and fell asleep. But he couldn't sleep. Guiguzi tossed and turned, always thinking about the bamboo slips of the wordless heavenly book, until he was dark. The bamboo slips were still rolled up and rolled up in front of him. He simply got up, lit a pine torch, and read the "Book of Heaven" by the light. This sight made him jump up in fright. Golden light flashed on the bamboo slips, and lines of tadpole text shone brightly. Guiguzi sighed: "Could this be the "Golden Book" handed down from ancient times?" Guiguzi's interest doubled for a moment, and he read it in one breath. , memorize it from beginning to end. It turns out that there is a Zongheng family letter recorded on it, which talks about the techniques of closing, reaction, internal control, resisting and flying tongs.