In the deep winter of the 3rd year of Hongde, Shuntian Dynasty, heavy snow buried Qingzhou.
The snow fell heavily, and a thick white fog blanketed the entire city, as if threatening to swallow everything in the world. A freezing wind howled past, sweeping the snow from the eaves into the air, scattering it like broken jade.
Chen Hui stood before the granary, wearing a dark blue official robe. Its seams had long been soaked by the snow, and its hem was covered in mud. Yet, he stood as straight as a pine, his gaze steady and sharp, exuding a commanding presence rare among scholars. Against the backdrop of the snowstorm, he looked handsome, maintaining complete calm and rationality.
At his cuff, a string of celadon abacus beads clicked softly with his movements—this was the "Luoshu Bead" of the Holy Scholar Academy, worn only by those who had mastered the *Nine Chapters on the Mathematical Art*.
"The old and weak line up for porridge! Strong men, clear three baskets of snow in exchange for a flatbread!" Chen Hui's voice was steady, carrying an unquestionable authority through the snowstorm.
"My lord, rioters are attacking the west granary!"
A sudden shout pierced the blizzard. From afar, the faint sounds of killing and yelling could be heard, like an angry tide buried beneath the snow gradually approaching.
Chen Hui's eyes narrowed, his deep gaze as sharp as a falcon's. He leaped onto a grain cart, the abacus beads in his sleeve rattling with the movement. With a wave of his judge's brush, the tip cut through the snowy curtain as he shouted: "Captains of Shen and Yi squads, lead your men and follow me to suppress the rioters!"
Chen Hui's gaze swept across the battlefield, calculating rapidly—seven ronin, twelve bailiffs, but the ronin stood in a "three-two-two" wild-goose formation, their left flank weak. He flicked the abacus beads in his sleeve and said in a low voice:
"Three on the left, four on the right, encircle them! The gap is at the southeast corner—"
Hearing this, the bailiffs shifted their formation, the clash of blades erupting in the snowy night. Brush in hand, Chen Hui leaped down from the grain cart and hurried to the west granary—and as he pushed his way through the chaotic crowd, this was the very scene that met his eyes:
Before the granary gates, a group of ragged rioters was smashing the door panels. Mixed among them, however, were several ronin carrying Moonrise Empire katanas at their waists. Their expressions were cold; some set fires, others drew their blades to attack women and children.
A fierce-looking ronin raised his blade, slashing towards a woman holding a child...
"Clang—!"
Before the blade could fall, a sudden flash of cold light erupted. The blade shattered instantly, exploding into countless flying fragments of calculation chips!
The ronin was thrown back by an astonishing recoil, slamming hard into the granary door, vomiting blood with terror filling his eyes.
Rushing over from afar, Chen Hui's pupils shrank. He followed the trajectory of the shattered blade—
On the eaves, a flash of cyan swept past, disappearing in the blink of an eye. The person had a copper calculation chip dangling from their sword tassel. With a light leap, they melted into the night. Most astonishingly, despite the thick snow on the roof, they left no trace behind!
"Treading snow without a trace?" Chen Hui murmured, his brows furrowing. "This is... Shushan's Moon-Treading Steps... But why would a Shushan disciple use calculation chips?"
At the other end, hidden in the darkness—
Lin Wanying silently pressed the "Exquisite Calculation Box" hidden in her sleeve. The calculation chip she just fired had come from this purple sandalwood mechanism box. The box was engraved with the Lin family's mathematical symbols—the only relic she managed to save the night her family was massacred.
A month ago, her master ordered her to assassinate the "wokou-colluding" Chen Hui.
"Master, if he is truly an evil man colluding with foreign enemies, why would he fight so desperately to protect the people and the grain?" she whispered. Her phoenix eyes were deep and complex as she gazed into the distance towards Shushan.
Three days before the spring floods arrived, Chen Hui received a secret report—someone of suspicious bearing had been seen prowling the upper reaches of the great Qingzhou River. He sent men to investigate through the night, and their report was chilling: several ronin had slipped into the upstream gorge, attempting to sabotage the mechanical linchpin of the river-suppressing iron ox. That iron ox was a relic of the previous dynasty, housing a Luoshu mechanism within—the last line of defense against the spring floods. Should the iron ox, this core body, be damaged, the dam of the great Qingzhou River (the failing body) would surely burst, and tens of thousands of Qingzhou's people would be buried beneath the flood.
Chen Hui immediately ordered the downstream dikes reinforced, while he himself went to inspect the riverbank, for he had to confirm whether the iron ox's mechanism could still function before the flood season. Yet as he stepped barefoot onto the dam, lowering his head to calculate the amount of sticky rice paste needed, he did not know—that the mysterious woman who had come to his aid on the snowy night was, at this very moment, watching him from the shadows.
Chen Hui focused intently on his calculations: "According to the *Book of City Building*, three thousand catties of sticky rice paste are needed to fill these cracks..."
Suddenly, a cold, clear female voice came from behind the willow trees: "You failed to calculate the Earth Dragon's (earthquake) turnover cycle. You should use the algorithm from the *Nine Chapters* to adjust it."
Chen Hui looked up abruptly, seeing a figure standing not far away—
Lin Wanying.
She wore a moon-white robe, her dark hair tied back. Standing by the misty riverbank, she looked aloof and untainted, like a solitary plum blossom in winter. Her sword tassel bore a copper calculation chip that swayed gently in the wind, as if whispering an ancient science. Her skin was slightly pale, like white jade untouched by the sun for years, yet she had a pair of deep, pool-like phoenix eyes that radiated unmistakable wisdom and sharpness.
Her gaze swept over the dam as sharply as a sword. She said coldly, "The gravel content of these stones exceeds thirty percent; they easily crack during tremors. If the Lin family's *Earth Measurement Classic* hadn't been slandered as a demonic book back then, your Qingzhou officials would have known this long ago."
Chen Hui was shocked: "You know of the Qingzhou Lin family?"
Lin Wanying's fingertips tightened slightly, faint white marks appearing on her palm. Of course she knew—that family of mathematicians annihilated by the court was her very bloodline!
She reined in her emotions, her tone unrippled: "I know there is a river-suppressing iron ox from the previous dynasty nearby. It can raise the old dam by two feet. I figure this will save an official who loves his people like you a lot of manual labor."
Ignoring Chen Hui's question, she turned and walked to the other side of the dam. Her fingers lightly tapped inside her sleeve; the "Exquisite Calculation Box" made a faint mechanical click, and a sliver of cold light popped out.
"Turn Nine Qian, separate soul Kun, see middle Kan... Yes, it's right here."
She leaped half a zhang, swinging her sword to cut away the vines. The vines flew apart, revealing a river-suppressing iron ox that had slept for a century.
"Here, this is the river-suppressing mechanical ox."
The iron ox was made of dark bronze, its body engraved with complex Luoshu patterns. Time had left faint green patina on its surface.
As the two approached the iron ox, the Luoshu patterns on its back suddenly glowed faintly, resonating with the Luoshu Bead in Chen Hui's sleeve, emitting a subtle hum.
"The Luoshu Bead should be able to activate this iron ox and trigger the dam mechanism. You can try it," Lin Wanying said softly.
With that, she stepped back a few paces and stood quietly aside, her arms crossed, as if testing Chen Hui's mathematical prowess.
Chen Hui took a deep breath and placed the Luoshu Bead into the mechanism's slot.
"Clack, clack—"
A muffled sound of turning gears came from inside the mechanism. The Luoshu patterns on the iron ox's back changed rapidly, and several complex symbols from the *Nine Chapters on the Mathematical Art* appeared on the control panel. Each button was engraved with a different mathematical formula.
Chen Hui glanced at it and said deeply, "It seems that aside from the Luoshu Bead, one must understand the *Nine Chapters* to calculate the corresponding operational data for this mechanism."
"Try substituting the second formula of the Earth Measurement from the *Nine Chapters*," Lin Wanying reminded him casually from the side.
Chen Hui calculated as he listened, muttering, "I think we also need to add the Heavenly Dipper method."
"And then find the common denominator," they said in unison, pausing at exactly the same moment to look up at each other.
Their eyes met in mid-air, instantly grasping each other's thought processes, astonished that their mathematical attainments were equally matched.
After a moment of silence, the corners of Lin Wanying's mouth curled up slightly, revealing a faint smile.
Chen Hui's heart trembled slightly, but he immediately suppressed the flutter, his fingertips carefully calculating on the mechanism's dial.
"Vertical twenty-seven, horizontal sixty-nine, product thirteen..."
"Sum forty," the two spoke the answer in unison.
Chen Hui turned his finger, adjusting the dial to "forty."
"Rumble—!"
The earth shook slightly. The mechanism that had slept for a century awakened. The stone structures on both sides of the riverbank slowly rose, increasing the dam's height by a full two feet. The surging river water was firmly blocked, kicking up a sky full of mist.
Once the mechanism finished operating, Chen Hui was about to offer his thanks when Lin Wanying suddenly crouched down, her fingertips brushing over a charred mark beside the iron ox's pedestal.
"Someone has tampered with this," she said, her voice sinking. "Three of the Luoshu lines on the mechanism's outer shell have been scraped away—had we not arrived in time, this iron ox would never have survived the spring floods."
Chen Hui's expression changed abruptly. He suddenly recalled the ronin mixed among the rioters on the snowy night—they had burned the granary and slaughtered the people not merely to create chaos, but to cover for another group sabotaging the core body.
"What they want is for Qingzhou's dam to burst," Chen Hui said in a low voice, his fist clenching. "Someone wants to use a natural disaster to destroy this city."
(As Chen Hui lowered his head to examine the mechanism, Lin Wanying turned her face aside, her gaze sweeping over his profile, and thought to herself:)
Master said he colluded with the wokou, that he sold out his country for gain... Yet would a man who betrayed his country stand from dusk till dawn in a snowy night for a few thousand piculs of grain? Would he, for the lives of tens of thousands of common folk, stand barefoot in the freezing river mud to calculate sticky rice paste?
She lowered her eyes; the Exquisite Calculation Box in her sleeve grew faintly warm, like a silent warning.
—If Master was wrong, then what was the truth behind the massacre of the Lin family?
"Since Magistrate Chen has thought it through and found the problem, I won't trouble you any longer. I shall take my leave."
Lin Wanying spoke softly, turned, and leaped onto the riverbank. Her figure quickly vanished into the misty riverside.
Chen Hui stood stunned, turning to gaze in the direction she had vanished. His brow, knit tight from the trouble he had just uncovered, abruptly eased, and he couldn't help but chuckle.
"This woman is unwilling to leave behind even a word of needless small talk. Could it be she fears saying even one more sentence to me?"
Yet, he felt an indescribable thrill in his heart, as if he had finally met someone in this world who could match him—not just as an opponent in martial arts, but as a soulmate in mathematics.
"Fire! The Wenmo Pavilion is on fire—!"
When Chen Hui arrived at the scene, the first thing he saw was not the fire, but several familiar figures along its outer edge—the katanas of Moonrise Empire ronin, flashing and gone in the firelight. They were withdrawing, and one of them clutched a heavy iron casket to his chest.
Chen Hui's pupils contracted—in the glow of the flames, he recognized one of them: it was the very ronin leader whose blade had been shattered by a calculation chip on the snowy night! The scar on his face remained as he now fled, the iron casket in his arms.
"It's them again!" Chen Hui gritted his teeth.
The bailiffs drew their blades and charged, locking in battle with the ronin. Chen Hui's judge's brush struck point after point, forcing back one ronin attempting to break out. In the melee, the iron casket fell and burst open—inside were ancient mathematical texts treasured by the Wenmo Pavilion, including, astonishingly, a forbidden transcript of the Lin family's *Earth Measurement Classic*!
Seeing their plan foiled, the ronin retreated while fighting and vanished into the night in a blink. Chen Hui had no time to give chase—the fire had already devoured half the library, and cries for help came from within the smoke.
"Save the people first!" he ordered through gritted teeth, turning to rush against the surging crowd into the blaze.
"Hurry! Line up the water buckets! Get the people out first!" Chen Hui's robes were blackened by smoke, the sweat on his forehead mixed with ash. He directed the firefighting teams to coordinate the water supply while working with the bailiffs to carry out the books that could still be saved. However, the fire in the east library had already consumed half the collection. Raging tongues of fire licked the wooden pillars, spreading to the load-bearing beams with terrifying "creak" sounds.
"Oh no! The load-bearing beam has burned through, the whole library is going to collapse!"
"Retreat! Everyone inside, get out quickly!" The firefighters fled in panic. Yet, just as everyone retreated, a tall figure pushed against the crowd and rushed into the fire. "Lord Chen!" A bailiff cried out in shock, trying to stop him, but it was too late.
Chen Hui's eyes were calm, and he charged into the building without hesitation. Thick smoke rushed at him, the scorching air almost suffocating. He flipped his judge's brush, the tip striking rapidly, precisely hitting several key points on a partially burned pillar.
"Crack!"
The pillar collapsed towards the fiercest flames! For a moment, the falling beam suppressed part of the fire, causing it to divert and buying a sliver of time for escape. Several firefighters took the chance to rush out. But—as the flames reversed, a burning crossbeam came crashing down with a loud boom, sealing the exit!
Chen Hui's retreat was cut off! He looked at the surging flames before him, giving a bitter smile, his tone light: "Miscalculated..."
But he didn't panic, instead showing a hint of self-mockery:
"Well, at least I got a few people out. Not a pointless death."
Right at that moment! "Boom!" A deafening sound of shattering came from the side wall. Through the flames, an icy sword aura tore through the thick smoke, slashing against a stone wall.
"The stone wall bears forty-seven percent of the load. I used the Pythagorean theorem to calculate the support point is right here—Break!"
Amidst the rolling flames, dust and rubble flew everywhere. The stone wall shattered, revealing an exit.
As the smoke cleared, a slender, beautiful silhouette emerged from the fire—Lin Wanying. Her white clothes fluttered, her long sword humming softly, like an orchid blooming in a sea of fire.
Her hair flickered in the firelight, reflecting an amber sheen. The copper calculation chip on her sword tassel vibrated slightly, as if still calculating something.
"Let's go!" she said coldly, her gaze meeting Chen Hui's through the smoke and sparks.
Chen Hui was stunned.
Lin Wanying didn't wait for him to react. She swung her sword—"Swish!" A burning wooden beam was sliced in half and fell to the ground, blocking the approaching flames.
She said as she walked, "I calculated the internal density of the wall using the Pythagorean theorem and the *Earth Measurement Classic*. The weakest structural point of this stone wall, its stress point, is exactly six feet to the right. Just enough to break open an exit."
Her voice remained calm, yet against the backdrop of the blazing fire, it felt extraordinarily resolute and composed.
"Is this... a fusion of the Lin family's mathematics and Shushan sword aura?" Chen Hui finally spoke, a flash of surprise and admiration in his eyes.
Lin Wanying turned her blade, pointing straight at the final crossbeam. "Shatter!"
"Crack!" The crossbeam broke, and the final obstacle collapsed.
Amidst the surging flames, Lin Wanying turned her head slightly. Her long hair blew in the heat wave, her voice low and firm—
"Master said that mathematics disturbs the sword heart. But I insist on proving—the lives the Lin family's methods can save are no fewer than those saved by the Shushan sword!"
The two broke free of the fire. Still catching his breath, Chen Hui immediately pointed to the iron casket the ronin had dropped earlier: "What they came to seize was this—the Lin family's *Earth Measurement Classic*."
Lin Wanying's body shuddered. She crouched down and opened the charred pages, her fingertips trembling slightly: "...This is the sole surviving copy, lost when the Lin family was massacred."
She raised her head, a cold light flashing in her phoenix eyes: "From the snow-night relief, to the sabotage of the iron ox upstream, to tonight's theft of these books—this was no act of the ronin alone. Someone must be directing them from the shadows. And that person..."
Chen Hui crouched and picked up a scrap of paper beside the iron casket that the fire had not fully consumed. On it were only half a line of words—
"...The remnants of the Lin clan are not yet rooted out; the mathematical classic must be retrieved at all costs..."
The latter half had been devoured by the tongues of flame.
He gripped the note tightly and looked up, exchanging a glance with Lin Wanying. Neither of them spoke, yet the same thought surfaced in both their hearts at once:
—Someone feared the Lin family's mathematics. Feared it enough to massacre a family, to burn books, to destroy an entire city to bury it.
The firelight slowly died out behind the two of them, but a far greater undercurrent had only just begun to surge.
But within this consuming inferno, something was sprouting—that indescribable flutter between the two of them.