The north wind of the twenty-fourth day of the twelfth lunar month whipped up fine snow, freezing the yellow dragon flags atop the Jinling city walls into ice sculptures.
Shen Xitang stepped into the Textile Bureau of the Inner Palace in her newly crafted deer-hide boots, only to halt at the threshold. Inside the courtyard, thirty-six looms were draped in white linen, as if in mourning for the dead.
"These are the new cloud-brocade weavers who arrived last month," Qingxing said, her fingertips trembling as she handed over the roster. "They suddenly vomited blood and died overnight..."
Shen Xitang lifted a white cloth; the deceased’s fingernails were embedded with indigo crystals. She dipped a crystal into a bowl of tea, and the oil slick that formed on the surface gave off the pungent scent of sulfur—the telltale sign of "Peacock Gall," a poison supplied exclusively to the Ministry of Works.
"Seal all dyeing vats immediately!" she commanded, tearing the ornamental jade pendant from her waist. "Bring me the 'Fire-Wash' chapter of *Creation of Heavenly Works*!"
Before the words had even faded, a thunderous crash echoed from the east wing as a loom toppled. When Shen Xitang rushed into the dye house, twenty pottery vats were bubbling; the liquid, which should have been indigo, now shimmered with an eerie peacock green. She plunged her silver hairpin into the dye, and the tip instantly became coated in black rust—someone had laced the dye with sulfur-copper, a material unique to the Japanese islands.
"Watch out, Miss!"
Qingxing’s scream was cut short by a whistling sound. Three crossbow bolts tore through the paper window, pinning themselves into the vat Shen Xitang had just been standing by. Tied to the arrow shafts was a slip of plain paper, the ink still wet: "When the third watch drum sounds, meet at the Chicken-Ming Temple pagoda."
At the hour of the Rat, the watchman’s drum, muffled by snow, beat against the window lattice. Shen Xitang stood in a hidden alcove on the top level of the Chicken-Ming Temple pagoda. Her monocular scanned the surface of the Qinhuai River, where seven painted boats drifted slowly along the ice. She pressed the Armillary Secret Key into the copper bell atop the tower; the clapper spun three and a half times, playing a melody from *The Battle Music*.
"Seal-holder Shen has quite the refined taste."
An old man in a python-patterned robe emerged from the shadows, a gilded hand-warmer in his hand engraved with the tiger tally of the Ministry of Works.
Shen Xitang gazed at a face seven parts similar to her second uncle’s and suddenly tore open her heavy cloak. "Minister Cao, your methods are impressive; you even dare to forge the Peacock Gall bestowed personally by the Emperor."
"Not as impressive as Seal-holder Shen’s skillful hands." Minister Cao kicked a wooden crate at his feet, spilling out ice silkworm silk soaked in poison. "How could looms restored using *Essentials of River Engineering* possibly produce clean fabric?"
A sudden volley of Pear Blossom Rain Needles erupted from Shen Xitang’s sleeve. As the steel needles pierced the hand-warmer, sulfur powder exploded into a cloud of indigo smoke. She vaulted onto the eaves, watching as all seven painted boats simultaneously released sky lanterns—the blood-red charms on the lanterns formed the very map of the *Nine Borders Defense* she had displayed at the imperial merchant competition.
"Release the river lanterns!"
The scarred boatman’s roar cut through the wind and snow. Shen Xitang shoved the secret key into the tower’s mechanism, and suddenly, three thousand ice lanterns rose from the surface of the Qinhuai River. This was the "Cold River Lock" she had restored according to *Creation of Heavenly Works*; the lanterns were filled with phosphorus, which would reveal the locations of the Ministry of Works' hidden caches upon contact with heat.
"Seize the thieves!"
Xiao Heng’s steel whip coiled around the mast of the third boat, the golden dragon head at the tip shattering the secret hold at the bottom of the hull. Bundles of Japanese sulfur poured into the icy river, igniting into a towering inferno upon meeting the phosphorus.
Amidst the heat, Shen Xitang saw Minister Cao fleeing toward the Drum Tower, the reflection of refined iron kneepads visible beneath his robes—the very equipment stolen from the Ministry of Works' hidden armory.
At the fifth watch, Shen Xitang stood in the charred ruins of the Drum Tower. The remnants of ice silkworm silk in her hand revealed a partial *Nine Borders Defense Map* when heated. She pressed the silk against the patterns of Xiao Heng’s steel whip, and the missing "Heavenly Pivot" position pointed clearly toward the newly built "Charity Granary" of the Ministry of Works.
"Check the ice cellars immediately!" she ordered, tearing off her imperial fish tally. "Use the Armillary dyeing method to inspect all official granaries!"
On the twenty-sixth day of the twelfth month, in the Charity Granary cellar, Shen Xitang’s deer-hide boots crunched over frosted blue bricks. She stopped abruptly in the southeast corner—the water seeping through the brick gaps shimmered with a sulfurous blue. She inserted the Armillary Secret Key into the gap; the hidden door groaned open, revealing twenty improved Shenji Crossbows gleaming in the cold. The scrolling vine patterns on the crossbow triggers matched those on Xiao Heng’s steel whip.
"Seal-holder Shen, look at this."
Qingxing handed over a soaked ledger; the ink became visible in the chill of the cellar: "Sixth year of Jiajing, purchased three thousand stones of Japanese copper, recorded as disaster relief grain."
Shen Xitang brushed over the Ministry of Works' wax seal on the edge of the ledger and suddenly tore open the interlayer of the cover—inside were copies of the border defense maps, transcribed onto scraps of Skysining Brocade.
"Pass the order to every granary!" she pressed the key into a gap in the ice wall. "Use the 'Cold River Lock' to seal all official grain!"
Amidst the firecrackers of New Year’s Eve, Shen Xitang stood before the rebuilt Textile Bureau. The thirty-six newly crafted water-powered looms hummed, the ice silkworm silk gleaming under the glazed lamps. She unfolded the imperial *Nine Borders Creation Map*, only to hear the crisp sound of ice shattering—twenty Red Horse Boats broke through the ice, their figureheads carved with the Xuanwu pattern of the Xuanji.
"Seal-holder Shen, it is time to settle the accounts."
Xiao Heng’s steel whip pointed toward the end of the canal, where smoke signals were rising from the newly built official granary. Shen Xitang draped the Skysining Brocade over her shoulders; the Big Dipper on the fabric caught the snowlight, casting winding Armillary patterns across the frozen river—the final resting place for the Ministry of Works' hidden outposts.
On the fifteenth day of the first lunar month, the beacons dyed the border walls of Jizhou red. Shen Xitang stood on the watchtower wrapped in fox fur, the copper rim of her monocular sticking to her fingers in the cold. She gazed at the rolling snow dunes beyond the pass, then suddenly turned the lens southeast—three miles away, twenty strings of horse tracks veered abruptly toward an abandoned beacon tower.
"Bring the *Nine Borders Defense Map*!"
On the sheepskin map Qingxing unfolded, that specific beacon tower had been circled in vermilion three times. Shen Xitang’s silver hairpin traced an annotation on the edge of the map: "Seventh year of Jiajing, Ministry of Works requested repairs." The cold hairpin tip suddenly felt a tiny protrusion; she tore open the sheepskin interlayer, revealing half a yellowed *Armillary Crossbow Platform Construction Diagram*.
"Lord Xiao, please bring three hundred pounds of saltpeter." She pressed the diagram against the parapet. "Before the third watch tonight, I want this beacon tower to spit out the truth."
At the third quarter of the hour of the Dog, Shen Xitang crouched beneath the ruins of the beacon tower. Her improved Luoyang shovel pierced the frozen earth; the brick shards brought up by the shovel tip shimmered with an indigo hue—this was the "Peacock Brick," specially made by the Ministry of Works to mark underground caches.
When the seventh shovel strike hit a hollow space, she sprinkled saltpeter powder into the icy water; the exploding clods of earth revealed a gilded door ring.
"It’s a Four-Images Lock from the Ministry of Works!" Xiao Heng’s steel whip swept the rust from the ring. "It requires the weights of the four seasonal military rations to open."
Shen Xitang took off her fish-tally pouch and emptied out four copper weights: the spring ration engraved with wheat ears, the summer ration carved with lotus pods, the autumn ration chiseled with chrysanthemum patterns, and the winter ration embossed with pine branches.
As the copper weights clicked into the keyholes, a roar of gears echoed from deep underground, and three thousand ice rats scurried out—these were beasts trained by the border army to deliver secret messages, each with an indigo ribbon tied to its claw.
"Follow them!"
The improved sleds skimmed over the snowfield as Shen Xitang’s phosphorus-filled tubes erupted into ghostly blue sparks. The pack of ice rats stopped in a snow valley ten miles away, all gnawing at a specific wall of ice. She inserted the Armillary Secret Key into a fissure, and the frozen earth suddenly collapsed, revealing twenty refined iron crossbow carts covered in oilcloth—the scrolling vine patterns on the crossbow arms were identical to those on Xiao Heng’s whip.
"It’s the improved 'Barbarian-Breaking Crossbow'!" Xiao Heng tore off the oilcloth. "These range markings... they’re three hundred paces beyond the current standard-issue crossbows of the Ministry of War!"
Shen Xitang brushed over the crossbow wheel, her fingertips coated in sulfur powder. "The rain of arrows that the Japanese used when they invaded last year—it was this type of crossbow."
She suddenly flipped open a hidden compartment in the base, and bundles of *Nine Borders Defense Map* copies spilled out, each corner stamped with the wax seal of the Ministry of Works.
When the fifth watch drum echoed through the border, Shen Xitang stood before a glowing red anvil. She placed a defense map over a piece of raw iron and struck it with a hammer. The sulfur ink revealed itself under the heat, showing a winding map of secret tunnels leading directly to the winter pastures of the Jurchen tribes beyond the pass.
"Bring me my woven brocade!" she tore the ice silkworm silk from her wrist. "Use the Armillary dyeing method to redraw the map!"
On the eighteenth day of the first month, the Ministry of War survey team marched into the snow valley. Shen Xitang unfolded ten yards of brocade; the morning sun shone through the warp and weft of the ice silkworm silk, casting an animated image of the border defense onto the snow. When the scene revealed a secret meeting between the Japanese delegation and a Jurchen leader, the Minister of War suddenly roared, "How dare you, witch, frame high-ranking officials!"
"My Lord, you might want to look closer at their waist tags." Shen Xitang splashed saltpeter water on the scene, and the secret mark of the Ministry of Works appeared on the waist tags of the Japanese in the image.
Before the Minister’s sword could be unsheathed, Xiao Heng’s steel whip had already coiled around his wrist—the inner layer of his refined iron bracer clearly bore the holographic construction diagram of the Armillary Crossbow Platform.
"What a fine Minister of War!" Shen Xitang tore open his official robe, the tattoo on his chest perfectly matching the lines of the crossbow mechanism. "During the Datong military payroll theft three years ago, those transport wagons used these exact modified crossbow markings!"
Thunderous hoofbeats erupted from beyond the pass, and Shen Xitang leaped onto the watchtower. Three thousand Japanese cavalry launched a surprise attack under the cover of the blizzard, the man in the python robe at the lead wielding an improved Barbarian-Breaking Crossbow, the arrowheads shimmering with the indigo poison of Peacock Gall.
"Turn the winches!" she waved her command flag. "Use the second form of the 'Cold River Lock'!"
Hidden sluice gates in the border wall slammed open, and a hundred improved water-cannon carts sprayed rain of liquid fire. As the Japanese cavalry fell into chaos within the sea of flames, Shen Xitang pulled the mechanism on the watchtower, and three thousand sulfur arrows, empowered by the crossbow carts, blanketed the snowfield.
As the last Japanese cavalryman turned into a pillar of fire, she gazed at the charred patterns emerging on the snow—it was the complete *Nine Borders Smuggling Route Map*.
"Lord Xiao, it is time to close the net." Shen Xitang pressed the Armillary Secret Key onto the border map; the missing Liaodong section suddenly appeared. "The true hidden cache of the Ministry of Works is beneath the ice at the mouth of the Liao River!"