The province of Yizhou was a vital stronghold in the heart of Shu, a place of majestic mountains and rivers, where the soil was fertile and the people prosperous. Exiting the city's western gate and following the Brocade River upstream for three li, one came upon a long street paved with slabs of blue stone. Ginkgo trees lined both sides, and every deep autumn, their golden leaves would carpet the ground like rich brocade. This street was the famed "Ginkgo Grove Street" of Yizhou, home to seven or eight medical halls and apothecary shops bustling from dawn till dusk with patients seeking consultation and prescriptions.
At the southernmost end of Ginkgo Grove Street stood a three-courtyard residence. Two stone statues of Xiezhi—the mythical beasts of justice—crouched before its gate, and upon the lintel hung a plaque of dark ebony wood inscribed with three gilded characters: "Half-Immortal Hall."
The master of Half-Immortal Hall was named Yan Benren, courtesy name Housheng. For three generations his family had practiced medicine, and by his generation, he had become the foremost physician in all of Yizhou. Doctor Yan was in his fifties, lean and spry, with a long beard of graying white flowing down to his chest. His gaze was gentle yet piercing; a patient seated before him often found that Doctor Yan had already deduced seven or eight tenths of their ailment before they even spoke. His skill in pulse diagnosis was exquisite. From the subtlest variations in the three sections of the Cun (wrist) pulse, he could discern the excesses, deficiencies, heat, and cold within the five viscera and six bowels. Rare and difficult diseases from hundreds of li around almost always resolved with a single dose of his medicine. Over time, the common folk bestowed upon him the elegant sobriquet: "Yan Half-Immortal" —meaning his medical skill bordered on the celestial, just half a step from transcendence.
Doctor Yan merely smiled at this, never taking pride in the title. In his hall, he had hung a couplet of his own calligraphy. The first line read: "With three fingers I gauge the pulse, knowing life and death." The second line read: "With one dose I restore spring, discerning Yin and Yang." The horizontal scroll bore the warning: "As if Approaching the Abyss." When asked why he chose such a cautionary phrase, he would say solemnly, "A physician holds the power of life and death. The slightest error can cost a life. Every time I take a pulse, I feel as though I stand at the edge of an abyss, treading on thin ice. How could I dare feel even a fraction of pride?"
One afternoon, the autumn sun slanted low, and the crowd at Half-Immortal Hall had gradually thinned. Doctor Yan had just seen off an old man suffering from cough and asthma and was sitting behind his desk, resting with his eyes closed, when he heard the sound of footsteps outside the hall. The footsteps were light but possessed a peculiar rhythm—heavy, light, heavy, light—as if someone with a limp was approaching.
Doctor Yan opened his eyes to see two figures entering the doorway.
The first was an old woman, roughly sixty years of age, her hair graying and her face deeply lined as if carved by a knife. She wore a coarse, ash-brown robe and leaned on a cane made of chaste tree wood. Bent at the waist and hunched in the back, she appeared no different from any ordinary country crone. Yet the moment she stepped through the door, Doctor Yan shuddered involuntarily, as if a draft of icy wind had snuck in through the crack of the door and crawled up his spine.
Behind her walked a young man in his early twenties. His features were passably handsome, but his complexion was pallid, and his left leg dragged with a slight limp—each step causing his shoulder to dip leftward, a clear sign that the leg was shorter than the right. He kept his head down, his eyes darting furtively about the hall's furnishings with a restless, shifting gaze.
Doctor Yan rose and clasped his hands in greeting. "Madam, have you come seeking medical attention?"
The old woman nodded, her voice hoarse and low. "I have long heard of the great name of Yan Half-Immortal. I came specifically to seek your aid."
"You flatter me. Please, Madam, have a seat."
He gestured to the round stool before his desk, then looked toward the young man. "Is this your son?"
"He is my son."
The old woman helped the young man sit but remained standing herself, leaning on her cane as if standing guard.
Doctor Yan did not insist. He sat back down and pushed the pulse pillow toward the young man. "Young sir, please extend your hand."
The young man hesitated a moment, then slowly placed his right hand upon the pillow. His fingers were long and pale, the nails neatly trimmed, but the fingertips held a faint, unhealthy bluish-white tinge. Doctor Yan placed three fingers upon the Cun section of the wrist, closed his eyes slightly, and concentrated.
As soon as he made contact, Doctor Yan's brow furrowed.
For an ordinary person, the pulse falls under the eight principles: floating, sunken, slow, rapid, slippery, rough, vacuous, and replete. Combined with the varying depths at the Cun, Guan, and Chi positions, there are twenty-seven distinct pulse images. In thirty years of practice, Doctor Yan had taken no fewer than a hundred thousand pulses—what kind had he not encountered? Yet the pulse of this young man stirred a strange, indescribable unease within him.
First, there was the location of the pulse. A normal Cun pulse lies along the radial artery, divided into Cun, Guan, and Chi, corresponding to the Upper, Middle, and Lower Burners respectively. This young man's pulse position seemed to deviate by a hair's breadth. Though the difference was minuscule, Doctor Yan's fingers were exceptionally sensitive and detected it immediately.
Second, there was the rate. His pulse beat four times per breath—neither fast nor slow, superficially normal. But as Doctor Yan counted carefully, he noticed that every seven or eight breaths, the pulse would secretly race for a single beat, then return to normal. This acceleration did not resemble the natural fluctuation of Qi and blood; rather, it felt as if something deep within the heart meridian had suddenly thrashed, only to be forcibly suppressed.
What unnerved Doctor Yan most, however, was the force of the pulse. Within the young man's vessels seemed to lurk two entirely distinct forces. One floated near the surface, tepid and unremarkable, like that of any ordinary person. The other lay sunken in the depths, profound and powerful, like a torrential undercurrent surging beneath the earth's crust, threatening at any moment to break through the surface and erupt. These two forces intertwined and repelled each other within his vessels, forming an eerie and unprecedented pulse image. In thirty years, Doctor Yan had never witnessed such a thing.
He had the young man switch to his left hand. The pulse on the left was largely the same, but Doctor Yan noticed that at the left Cun position—the region corresponding to the heart—the underlying undercurrent was significantly more turbulent than on the right. The Heart is the Sovereign Ruler, governing the blood and housing the spirit. If the Heart Meridian was diseased, it was no minor ailment.
Doctor Yan withdrew his fingers and was silent for a moment, his gaze sweeping across the young man's face. Upon closer inspection, he discovered further clues. Though the young man's complexion was pale, a faint, extremely subtle redness glowed beneath his cheekbones. It was not the healthy flush of robust Qi and blood, but rather as if something beneath the skin emitted a faint luminescence. His pupils were also slightly larger than average, and the whites of his eyes held a bluish tint. Staring too long gave one the unsettling illusion that a second pair of eyes lurked within the depths of those sockets.
A suspicion had already formed in Doctor Yan's mind. But with decades of experience, he knew better than to speak bluntly in front of a patient. He cleared his throat lightly. "Madam, might I have a word in private?"
The old woman's eyes flickered. She stepped closer, leaning on her cane. "Whatever the Doctor has to say may be said openly. My son can hear anything."
Seeing she was unafraid, Doctor Yan chose his words carefully. "Your son's pulse is indeed... unique. Forgive my forwardness, but I must ask—was the injury to his leg caused by an arrow?"
The old woman's expression darkened slightly. The young man shuddered violently, jerking his head up with a flash of ferocity in his eyes. The old woman placed a hand on his shoulder, and he lowered his head once more.
"Your reputation is well-deserved, Doctor."
The old woman's voice remained hoarse, but her tone carried a chill. "Indeed. It was an arrow wound. Shot by a hunter."
Doctor Yan nodded and pondered. "An arrow wound injures sinew and bone. During healing, the left leg became shorter. If it were merely a matter of sinew and bone, it would not be untreatable. However, based on my diagnosis, I perceive another... another peculiar energy within your son. This energy clashes with his own Qi and blood, obstructing the meridians and preventing medicinal strength from reaching the source of the illness. Unless this energy is first harmonized, even the finest bone-setting salve will yield little effect."
He had chosen his words with extreme diplomacy. "A peculiar energy"—that was the phrase he settled on after much deliberation. In truth, the moment he took the pulse, he had concluded that the deep, turbulent undercurrent was no human attribute. It was Demonic Qi.
Upon hearing this, the lines on the old woman's face seemed to deepen further. She stared fixedly at Doctor Yan, her gaze sharpening until it pricked like a pair of daggers.
"Doctor Yan."
Her voice suddenly shifted. Gone was the hoarse, aged rasp. It became low and resonant, imbued with an indescribable authority. "Since you have perceived it, I will not deceive you. My son is no ordinary human. There is no need for you to feign ignorance. I came today to ask but one question: Can you heal this leg, or can you not?"
The matter was now fully laid bare.
Doctor Yan inhaled deeply and slowly rose to his feet. In thirty years of practice, he had encountered many strange cases and heard whispers of spirits and monsters taking human form to seek medical aid, but this was his first personal encounter. To claim he was unafraid would be a lie. His palms were slick with cold sweat, and his inner garments were soaked through at the back. Yet his lifelong practice was founded upon the principles of Righteousness. If he showed fear now, it would not only tarnish the reputation of Half-Immortal Hall but also betray the three decades he had dedicated to the Way of Medicine.
He steadied his nerves and met the old woman's gaze squarely, his expression neither servile nor overbearing. He cupped his hands. "Since you have spoken frankly, Madam, I shall do the same. Within your son's pulse lies a force not of human origin. This force is entangled with his own lifeblood. To treat the leg, one must first regulate this force. Forgive my bluntness—I have practiced medicine for thirty years, but I treat humans, not spirits. Your son's constitution is vastly different from a mortal's. I have no confidence in treating it."
The old woman's face fell completely. She slammed her chaste tree cane heavily against the floor. There was a dull thud—yet the sound did not resemble wood striking brick. It was more akin to something of immense weight crashing against the ground. The entire hall trembled faintly. The teacup on the desk rattled against its saucer, and the brass drawer pulls on the medicine cabinet clinked and jingled.
"No confidence?"
The old woman gave a cold laugh. The wrinkles on her face seemed to writhe with a life of their own, her visage flickering eerily in the autumn sunlight. "You are the foremost physician in Yizhou, hailed as Half-Immortal, and you say you have no confidence? I think you are unwilling to treat him, not unable!"
Before the words had fully faded, she suddenly raised her cane and brought it down again with tremendous force.
The impact was ten times heavier than before.
BOOM! A thunderous crash echoed through the hall. The blue floor tiles beneath the tip of her cane shattered, cracks spider-webbing outward in all directions, reaching the distant walls in an instant. At the same time, an invisible wave of force erupted from her body, like a gale-force wind appearing out of nowhere. Medical texts on the desk fluttered and scattered, pages flying wildly. The pulse pillow was hurled into the air, spinning end over end before slamming into the wall. Drawers in the apothecary cabinet flew open of their own accord, and the herbs within—Angelica, Astragalus, Rehmannia, White Peony, Lovage, Poria—were scooped up as if by invisible hands and flung in every direction.
The young man rose to his feet, his eyes blazing with ferocity. A low, guttural growl escaped his throat, like a beast threatening its foe. His lips parted slightly, and in the light, his teeth gleamed with a sharp, cold edge, utterly unlike human dentition.
Doctor Yan stumbled backward, his back slamming against the wall. Dust and powdered herbs filled the air, making him cough repeatedly. But looking upon the wreckage of his hall, an unexpected calm settled over him. When terror reached its zenith, it sometimes transmuted into a strange, unshakable composure.
He straightened his robes, brushed the herbal dust from his beard, and stood tall, clasping his hands behind his back. His gaze was serene as he regarded the raging crone.
"Madam."
His voice was not loud, but every word was distinct. "Even if you tear down this entire Half-Immortal Hall, my answer remains the same. It is not that I will not treat him; it is that I cannot."
The old woman's raised cane hesitated.
Doctor Yan continued, "A physician has his limits. When I diagnose and prescribe, I rely on the Four Examinations—Observation, Auscultation, Inquiry, and Palpation—and the Eight Principles—Yin/Yang, Exterior/Interior, Cold/Heat, Deficiency/Excess. All of these apply to humans. Your son's constitution is different. His meridians and the flow of his Qi and blood are unique. If I rashly administered medicine, not only would it fail to heal his leg, it might very well endanger his life. My refusal is not evasion; it is the fear of harming him."
He paused, letting his gaze linger on the old woman's face. "If you truly wish to heal his leg, Madam, you would do better to seek a master versed in the profound mysteries of Heaven and Earth. I am merely a mortal physician. I can heal humans, not spirits. This is not an excuse; it is the simple truth."
His words were delivered with dignity and composure, acknowledging his limitations while offering her a path to retreat with grace. The old woman slowly lowered her cane. Though the anger had not entirely left her face, the violent, oppressive aura around her had noticeably subsided.
She stared hard at Doctor Yan for a long moment, as if judging whether his words were sincere or mere evasion. Doctor Yan met her gaze openly, his own eyes clear and righteous, without a trace of evasion.
Finally, she let out a cold laugh and tapped the floor lightly with her cane. This time, there was no roar, no tremor—only the soft click of the tip against the broken tile.
"So be it."
Her voice had returned to its initial hoarseness. "You are a man of some backbone. I will not make trouble for you."
She turned and walked toward the door, the young man limping behind her. As she reached the threshold, she stopped abruptly and turned her head slightly, half her face shrouded in the shadow of the door frame.
"Doctor Yan, I shall remember the words you spoke today."
Her voice was low and deliberate. "You will not treat him. I do not blame you for that. But if you breathe a word of what happened here today..."
She did not finish the sentence. Instead, she merely narrowed her eyes slightly. And within those narrowed slits, Doctor Yan clearly saw two points of eerie, jade-green light—exactly identical to the ones Zhao Dalang had witnessed in the fissure on Yanmen Mountain.
Then she withdrew her gaze, leaned on her cane, and with her limping son, walked out the door of Half-Immortal Hall, step by step.
The autumn sun still shone slanted. Ginkgo leaves swirled down in the gentle breeze. Pedestrians passed by on the street, none noticing anything unusual about the mother and son. The old woman, hunched and shuffling; the young man, limping behind with his head bowed—they looked like nothing more than an ordinary country youth, sickly and infirm.
Amidst the wreckage of his hall, Doctor Yan watched their silhouettes gradually disappear at the far end of Ginkgo Grove Street. Not until they had completely vanished from sight did he let out a long, shuddering breath, steady himself against the wall, and slowly sink into his chair.
His hands were still trembling.
After a long while, he summoned his apprentice and instructed him to tidy the hall. The apprentice gaped, speechless at the destruction, but before he could ask a single question, Doctor Yan waved his hand dismissively. "Do not ask. As for today's events, pretend you saw nothing."
The apprentice dared not inquire further and bent to the task of cleaning up. Doctor Yan sat alone behind his desk, gazing at the falling ginkgo leaves outside the window, lost in profound contemplation.
He recalled the surging undercurrent deep within the left Cun pulse of the young man. He recalled the twin points of jade-green light within the old woman's narrowed eyes. He recalled the words she had left unspoken.
"The Fox Pulse."
He murmured to himself, his fingers tapping lightly on the desk. "That was the Fox Pulse."
Doctor Yan had spent decades refining his study of sphygmology. He had once read a passage in an ancient medical text passed down from his ancestors. The author was a wandering physician, and the book, aside from standard medical theories and prescriptions, contained an appendix—a curious essay titled "Discriminating the Anomalous Pulses." The text listed several pulse images "not of human origin": The Fox Pulse, sunken and forceful, like a hidden spring surging from the earth; The Serpent Pulse, slippery and cold, like hoarfrost on chilled iron; The Tiger Pulse, vast and fierce, like a gale sweeping fire; The Ape Pulse, hurried and urgent, like driving rain upon leaves...
When Doctor Yan had first read that essay, he had dismissed it as the fanciful superstition of the ancients. Today, having personally taken the Fox Pulse, he knew that the ancient text recorded genuine truths.
"That old fox has at least three or four hundred years of cultivation," he mused silently. "She took human form to seek my help, likely out of sheer desperation. The arrow wound on that young fox damaged the sinew and bone. Mortal trauma salves are of little use to their kind, and the foxes' own healing arts cannot treat such structural injuries. That is why she came to me."
Thinking this, he felt a flicker of sympathy for the old fox's earlier rage. For the sake of her son, she had transformed, traveled a thousand li from Yanmen Mountain to Yizhou, and humbled herself—setting aside centuries of pride—to beg a mortal physician for help. Only to be told "I cannot treat this." Anyone would have been angered by such an outcome.
"But I truly cannot treat it."
Doctor Yan sighed and shook his head. "The Fox Pulse is utterly different from the human pulse. I cannot even grasp the patterns of its Qi and blood flow—how could I dare prescribe medicine? What if I used the wrong ingredient and killed the fox? Would that old vixen ever let the matter rest?"
He rose and walked to the apothecary cabinet, looking at the herbs his apprentice had retrieved. He picked up a slice of Angelica root, holding it to his nose. The medicinal fragrance cleared his mind and settled his nerves.
Suddenly, he recalled something. He hurried to his desk, retrieved the ancient family text from a drawer, and flipped to the section titled "Discriminating the Anomalous Pulses." On the yellowed pages, tiny regular script crowded the lines. He read carefully, line by line, until his gaze halted at the final paragraph.
The text read: "Regarding the Fox Pulse: Its Qi sinks and lies hidden beneath the Chi section. It beats with strength, like a spring welling from the ground. Foxes are suspicious by nature, and their Qi is likewise winding; thus, their pulse path meanders, unlike the straight path of the human pulse. To regulate the Fox Pulse, one must gauge the Fox's Heart with a Human Heart, and guide the Fox's Qi with Human Qi. Yet human and fox tread different paths. Though this method is possible, it cannot be performed by one lacking great stability of mind and great wisdom."
Doctor Yan closed the book and exhaled deeply. So there was a method—but it was impossibly difficult. "Gauge the Fox's Heart with a Human Heart, guide the Fox's Qi with Human Qi." This was not medicine; this was the practice of a Daoist adept. He, Yan Benren, was merely a mortal with above-average medical skill. How could he possibly accomplish such a thing?
"Forget it."
He replaced the book with a wry smile. "Such transcendent arts are beyond the reach of this old man. If that old fox has the karmic fortune, she will eventually find a master capable of healing her son."
The sun set in the west as dusk deepened. The ginkgo trees before Half-Immortal Hall rustled in the evening breeze, their golden leaves drifting down one by one to carpet the blue stone path. The apprentice lit the lamps, and the soft, warm glow filtered through the paper windows, casting a welcoming square of light upon the street.
Meanwhile, on the official road heading north out of Yizhou, the old woman walked ahead, leaning on her cane, while the young man limped behind. They walked in silence. After a long while, the young man finally could not restrain himself. His voice was tinged with grievance and frustration. "Mother, that Yan Half-Immortal was clearly unwilling! 'Not that I will not, but that I cannot'—it was all just an excuse!"
The old woman did not turn around, nor did her pace falter.
"He was not lying," she said flatly. "He truly cannot cure you. I could see it. That Doctor Yan is an honest man. If he says he cannot cure it, then he genuinely cannot."
"Then what do we do?" The young man's voice took on a quavering edge. "Must your son limp like this for the rest of his life?"
The old woman finally stopped walking. She turned to face her son. In the twilight, her face appeared exceptionally aged, the lines at the corners of her eyes as sharp as knife cuts. She reached out a gaunt, weathered hand and gently stroked Hu Chu'er's head.
"What is the rush?"
Her voice was low and slow. "There are heavens beyond heavens, and masters among men. If there is no one in Yizhou who can heal you, we will go to Jingzhou. If not Jingzhou, then Yangzhou. The world is vast. There must be someone who can heal your leg."
She withdrew her hand and turned back toward the north. In that direction lay Yanmen Mountain—her home, her grotto, the foundation of her centuries of cultivation.
"And if no one in all the world can heal you," her voice wavered slightly on the evening wind, "then I shall cultivate the skill to do it myself."
Hu Chu'er gazed at his mother's stooped silhouette. A lump rose in his throat, and he could utter no further complaint. He lowered his head and limped after her.
Twilight descended, and the figures of mother and son gradually melted into the northern horizon. In the distance, the outline of Yanmen Mountain glowed a deep, mysterious gray-blue against the last hues of the sunset. Within that great mountain, a pure white fox still waited at the entrance of a cave, watching for her mother and brother to return home.