The scholar Jia Zilong of Chang'an happened upon a man of dashing demeanor in a neighboring alley one day. Asking his name, the man replied, "I am called Zhengsheng." Jia Zilong immediately developed an admiration for him and prepared calling cards the next day to visit his residence, going three times in succession, yet Zhengsheng was never home.

On the fourth attempt, Jia Zilong had first ascertained that Zhengsheng was indeed within, and only then proceeded to call. Zhengsheng avoided the meeting, but Jia Zilong searched everywhere and finally located him. Zhengsheng, having no recourse, finally hosted a banquet. The two conversed intimately, delighting in each other's company. Jia Zilong produced the savings he carried and ordered his page boy to fetch wine. Zhengsheng was a prodigious drinker and skilled at witty banter; before long, the wine ran low, with little remaining. Still unsatisfied, Jia Zilong couldn't help but complain.

Zhengsheng smiled faintly and reached out to open a bamboo box, drawing forth a magnificent jade cup. The cup was exquisitely fashioned but lacked a bottom. Zhengsheng poured the remaining wine from the flagon into the cup; it filled perfectly, the liquid resting steadily, neither spilling over nor leaking out. Zhengsheng then took up a small ladle and continuously ladled wine from the cup back into the flagon; the flagon became full, yet the wine in the jade cup remained unchanged, not diminishing by a single drop.

Jia Zilong cried out in astonishment and begged Zhengsheng to teach him this secret art. Zhengsheng remarked, "Brother Jia, you are excellent in every way, save for one flaw: excessive greed. This is precisely why I was reluctant to meet you. This is an immortal secret art—how could it be taught to a mortal man?" Jia Zilong retorted, "You wrong me! Where am I greedy? My occasional surge of lavish desire stems only from my fear of poverty." With a burst of laughter, he cupped his hands in farewell.

From that day forward, the two men visited each other without cease. Whenever Jia Zilong found himself in straitened circumstances, Zhengsheng would produce a piece of black stone, chant an incantation while grinding refuse, and in an instant, the rubble would transform into silver—though the quantity was always limited, just enough for expenses, never an extra fraction.

Jia Zilong often grumbled, "Why not grind a little more?" Zhengsheng would chuckle, "I told you you were greedy, didn't I?" Jia Zilong remained silent, pondering, "It seems that asking him openly will likely result in refusal." A new plan formed in his mind: he would steal the black stone while Zhengsheng slept soundly and use it for leverage.

One day, Zhengsheng fell asleep after drinking, and Jia Zilong searched his person for the black stone. Unbeknownst to him, Zhengsheng was not deeply asleep and noticed at once. He sighed, "Brother Jia, you truly lack conscience; I cannot associate with you any longer." With that, he took his leave.

A year passed in the blink of an eye without any sign of Zhengsheng. One day, Jia Zilong went for a stroll by the river and spotted a piece of black stone on the sandy bank, crystalline and shining, very similar to the one Zhengsheng possessed. Overjoyed, he immediately picked up the stone, treasured it, and brought it home.

Several days later, Zhengsheng suddenly appeared, looking distraught. Jia Zilong offered words of consolation, to which Zhengsheng replied, "What Brother Jia saw the other day was the Stone of Transmutation of the Immortals. I once followed the Daoist Baozhenzi in cultivation; seeing my upright character, he gifted me the Stone of Transmutation. Drunk the other day while passing the riverbank, I accidentally lost the stone. Upon consulting an oracle, I learned it had fallen into Brother Jia's hands. If Brother Jia honors the 'Debt of Return' I owe him and returns the stone, I shall surely reward you."

Jia Zilong laughed, "I have never deceived a friend in my life; that is correct, your stone is indeed in my keeping. But in the old days, when Guan Zhong and Bao Shu were friends, Guan Zhong was impoverished, and Bao Shu often supported him. My situation now is no different from Guan Zhong's. How do you intend to repay me?" Zhengsheng said, "I will give you one hundred taels of silver."

Jia Zilong responded, "One hundred taels of silver is certainly a considerable sum. But please teach me the incantation; I wish to personally test the transformation of stone to gold, thus fulfilling a long-held desire." Zhengsheng cautioned, "Teaching you the incantation is possible, but I fear your greed will prove boundless, and you will break your word." Jia Zilong insisted, "You are an immortal; how can you misunderstand me? Am I, Jia, a man who would betray a friend?"

Zhengsheng, unable to refuse, imparted the incantation to Jia. Jia Zilong spotted a huge boulder on the steps, intending to use it to test its efficacy. Zhengsheng quickly restrained him, frowning, "Too big." Jia Zilong sighed, bent down, picked up half a grey brick, and placed it on an iron anvil, saying, "Half a brick—surely that is enough?" Zhengsheng was a man of pure sincerity and suspected nothing, nodding his head.

Little did he know that Jia Zilong was cunning; while grinding, he only ground the iron anvil and not the brick. Seeing this, Zhengsheng's expression soured, and he prepared to snatch back the black stone, but Jia Zilong was swift. With a series of touches here and there, in the blink of an eye, the iron anvil, weighing over ten catties, was entirely transformed into gold, only then was the black stone returned.

Zhengsheng sighed, "Since matters have come to this, what more is there to say? However, if I casually bestow fortune upon Brother Jia, I will surely incur heavenly punishment. If Brother Jia does not forget our old friendship, please atone for my sin by sponsoring one hundred coffins and one hundred padded winter coats. I wonder if you would be willing to help?"

Jia Zilong replied, "Rest assured, I am no miser. Since the gold was easily acquired, it should indeed be used to perform more good deeds." Zhengsheng was greatly pleased and took his leave. Jia Zilong became wealthy overnight, abandoning literature for commerce. He engaged in trade while simultaneously aiding the poor, and in less than three years, he had completed the distribution of all the coffins and padded coats.

On this day, Zhengsheng suddenly appeared, taking Jia’s hand and saying, "Brother Jia, you are truly a man of your word! Since our last parting, I was impeached by the God of Fortune and had my immortal status stripped by the Jade Emperor. Fortunately, Brother Jia accumulated merit on my behalf; my karmic debt is now cleared, and I am free from further punishment. I hope you continue to do good, and you shall receive greater fortune and longevity."

Jia Zilong inquired, "What office did you hold in the Heavenly Court?" Zhengsheng replied, "I was originally a fox spirit who achieved ascension and ultimately transcended the cycle of life and death. Due to my humble origins, I dared not commit evil in my life and never did anything wicked." The two reconciled, and Jia Zilong lived to be over ninety, maintaining contact with the fox immortal thereafter.

The Debt of Return: When the famous Tang official Pei Du was young, he lived in destitution. A certain physiognomist examined his face and declared, "Young master, your countenance is extraordinary; you will either achieve the highest ministerial rank or starve to death." Pei Du merely smiled upon hearing this and paid it no mind.

One day, Pei Du visited Xiangshan Temple for recreation. In the Buddha Hall, he saw a woman carrying a satchel. The woman's face was etched with sorrow; she placed the satchel on the ground, knelt in prayer, and then hurried away, leaving the satchel behind in her haste, forgetting it entirely.

Pei Du picked up the satchel and opened it. Inside lay two jade belts and one rhinoceros-horn belt, each item valued at a thousand gold pieces. As dusk fell, the woman returned, searching anxiously for her satchel. Pei Du asked her the reason, and the woman wept, "My father was framed and imprisoned without cause. I managed to borrow three belts to bribe the officials and secure his release, but I have lost them! What am I to do?" Pei Du asked about the size, shape, and specific characteristics of the belts, which the woman described perfectly.

Pei Du nodded, returned the satchel to the woman, who was overjoyed. She took out the rhinoceros-horn belt and offered it to Pei Du, but he refused and turned to leave. Later, Pei Du encountered the physiognomist again, who said, "Young master must have accumulated great virtue; your future path is boundless and limitless."

The physiognomist was not mistaken. Pei Du passed the Jinshi examination at the age of twenty-five, served in politics for several decades, rising to the rank of Chancellor, was ennobled as Duke of Jin, and served four successive emperors, truly becoming a statesman of four reigns with eminent status.