The following story is from the Qing Dynasty Yu Jiao's notebook novel "Dream Factory Miscellaneous Works", which has been slightly changed when translated.

In the land of Western Shu, there was a young man surnamed Yan, who claimed to be the descendant of Yan Junping (a scholar of the late Western Han Dynasty, a master of Yixue, who knew astronomy, recognized astrology, was good at divination, and was very prestigious in Shu, respected by the people and literati, during the Tang and Song dynasties, Li Bai, Zhang Jiuling and others also mourned, according to legend, he once predicted That Wang Mang usurped power), and would calculate divination.
In order to divinate, Yan Boy built a small room on the side of the road to calculate the fortunes of others, but the business was very poor, and his life was also very poor, because there was almost no income.
One morning, Yan Teenager set up a stall and was preparing to open a fortune teller. A man (called Zhang Ling, for convenience) came to him, spoke in an accent like Wu Nong's soft language, and said: Today, I want to borrow your stall to give people a fortune, and when it gets dark, I will give you silver five or two as a reward, how? When Yan Shaonian heard this, he quickly promised Zhang Ling to give up his position and watch from the side.
At noon, a man walked in small steps to do the math. Zhang Ling arranged the props, counted them, and suddenly attached his ear to the guests, saying: Give me the ten gold in your arms, and I will show you a way to live. When the guests heard it, they were suddenly sweating, and seemed to be very scared, so they quickly pulled out the gold, and sure enough, it was twelve, and gave it to Zhang Ling.
Zhang Ling told him: Twelve miles to the southwest, there is an ancient cellar, you hurry there to hide, but you can't enter through the main entrance, otherwise it is difficult to escape, you have to go through the hole above, and you must hide it after you enter. When I was about to arrive at Shen, I heard crows calling from the treetops, so I hurried out and ran in the southeast direction, so that I had no worries.
When the man heard about it, he hurried to the southwest.
After a while, a few people came, looking left and right, as if looking for someone. After seeing the divination stall, he rushed to divination. Zhang Ling continued to draw props, and soon he said: Are you arresting fugitives? One of them said: Yes, a prisoner escaped this morning, can the master calculate where he ran? After Zhang Ling's deduction, he said: The fugitive has not run far, give me five or two pieces of silver, and I will tell you his hiding place again, to ensure that you can find a place, if not, I will double the compensation to you.
Several people gathered for a moment and gave Zhang Ling five or two pieces of silver, and Zhang Ling took the silver and said: Hurry to the southwest land, see an ancient kiln, you can catch the fugitive, go quickly, you can't catch it when it's late.
When the sun was about to set, several people came back, shouting for money, and said that the calculation was not accurate, and said: Eleven or twelve miles to the southwest, there is indeed an ancient kiln, the door is covered with a pile of firewood, and there are many spider webs, and there are no footprints at all. If someone goes in, at least the firewood will move away, and the spider web will break! Unless the prisoner is a fly or an earthworm and finds a small gap to drill into, he will never enter.
Zhang Ling said angrily: You have really delayed a big thing, all the kilns, there must be holes in the top that are transparent and transparent, and the fugitives do not enter through the gate, can't they enter through the large holes above? When a few people listened, they immediately felt that it made sense, but at this time, I was afraid that it was too late to chase it, and I couldn't help but be discouraged.
Seeing this, Zhang Ling said: I will help you calculate it again for free. After some deduction, he said: According to the gua xiang, although the person ran away, something was left in the kiln, and this thing can be used as physical evidence. I'll go with you, and then I'll be able to see that no one can fool anyone. If I don't count correctly, then I'll pay you double the silver.
Yan Shaonian had always been curious, so he also wanted to follow along, and Zhang Ling agreed.
The group walked for half an hour and found the ancient kiln. A few men removed the firewood, picked up the cobwebs, and entered through the door. Sure enough, the crowd saw the footprints, and through the light, they saw that there was indeed a large hole in the ancient kiln that could allow one person to enter and exit, and there was a belt on the big hole, and the fugitive should come down through the belt and go out through the belt.
Seeing this, the few people who were pursuing the fugitives had nothing to say, did not ask for money anymore, took the belt and left.
Back at Yan Juvenile's stall, Zhang Ling took out five or two pieces of silver and handed it to Yan Juvenile. However, Yan Shaonian refused to ask for it, knelt down in front of Zhang Ling, and said: Teacher Father, your divination and fortune-telling skills are really too divine! I am willing to worship you as a teacher and learn the skills of the master, in this way, I can also be regarded as re-learning the skills of the ancestors, if I can succeed, I am very grateful, and I will not give up.
Zhang Ling said, "I can't pass on my skills to you." When I was learning from Master, Master had admonished me. Yan Teenager asked him what kind of admonition he was.
Zhang Ling said: Before, I begged for food everywhere to feed my old mother, but I still couldn't eat enough to wear and didn't warm up every day. One day, I suddenly met a Taoist monk, who looked at me as filial and obedient, and felt that I was pitiful, taught me the art of Liu Ren (a kind of ancient Chinese court astrology, which is collectively known as the three styles with Taiyi and Suijia), and said to me, every day you earn enough money to eat and dress, don't be too greedy, and don't use this skill to get rich. It cannot be easily taught to people with sound limbs, no physical disabilities, or people who do not deserve pity. Otherwise, there will be retribution.
Yan Shaonian did not understand and asked him why he had made such a rule.
Zhang Ling said slowly: At first, I couldn't figure it out, but then I knew. Those with sound limbs are basically people who can completely support themselves, and such people naturally cannot teach their skills, otherwise everyone wants to get something for free. Those who are physically disabled cannot support themselves, so they can teach their skills, but at the same time they cannot be greedy. And a small number of people with sound limbs, when encountering changes, can not support themselves or their relatives, this kind of poor people can also be taught.
Yan Shaonian understood, probably because he wanted to restore the glory of his ancestors, or to make more money, so he said: Since this is the case, it is also very easy. He blinded his own eyes and worshiped Zhang Ling as his teacher, and Zhang Ling did indeed teach him the art of the Six Renes.
After the story is told, seeing this, I can't help but sigh: Yan Teenager smoked his own eyes, is it because the days are too difficult? However, Zhang Ling also said that learning the art of the Six Nobles cannot be greedy and rich. It seems that he was blinded in order to restore the honor of his ancestors, which is really a cruel person.