On the Qinhuai River, ice floes collided with the hull, emitting crisp, jade-like chimes. Shen Xitang stood on the observation deck of the imperial merchant ship, wrapped in a fox-fur cloak. Her brass hand-warmer was engraved with the words "Heavenly Works," a recent imperial bestowal.
The bitter winds of the twelfth lunar month swept across both banks of the canal. She watched the laborers breaking ice to transport salt on the frozen surface, then suddenly aimed her spyglass at Yanziji, three miles away. The eaves of the newly erected official granary there aligned perfectly with the coordinates of the hidden markers noted in the *Canal Dragon Vein Map*.
"Open the sluice and release the ice rafts!"
Amidst the rhythmic chants of the scarred boatman, twenty modified ice sleds slid into the waterway. These were "Lingyin Carts" that Shen Xitang had reconstructed according to the *Essentials of River Engineering*, their bases embedded with sharkskin specially crafted by the Ministry of Works, generating heat and preventing slippage upon contact with ice.
As the lead sled smashed through the granary gate, the brass bells on the eaves rang out in unison, startling a flock of crows.
"Miss, watch out!" Qingxing pulled her down just as three crossbow bolts embedded themselves in the mast behind them. The arrowheads bore chrysanthemum patterns, while the fletchings were made from scraps of Skysining Brocade from the Jiangning Imperial Textile Factory.
Shen Xitang plucked a fletching to examine it closely, then suddenly threw off her heavy cloak. "Change course! There are iron caltrop nets beneath the ice!" She tossed her hand-warmer onto the ice. The silver-frost charcoal inside burst into flames upon contact with water, illuminating a dense web of sharp iron barbs beneath the ice—the "Cold River Lock" commonly used by the Ministry of Works navy.
The ship's keel groaned with a teeth-gritting friction. Xiao Heng’s Steel Whip shattered the ice armor on the bow. "The Shen Family's salt permits have already been approved; why risk storming the official granary?"
"Has Your Excellency ever heard of the 'Ice-Salt Evasion'?" She pulled out her salt permit; the edges of the vermilion official seal were haloed in indigo. "This year's new salt is mixed with sulfur from the Wa state; it reveals the Ministry of Works' secret marks when heated." As she spoke, she held the permit near the charcoal brazier, and a partial impression of a Tiger Tally emerged.
Suddenly, chimes and stone bells rang out from within the granary. Shen Xitang watched seven Kongming lanterns rise from the roof. She triggered a mechanism in the ship's hidden compartment, and twenty modified God-Arm Crossbows fired phosphorus-tipped arrows. The moment the rain of arrows pierced the lanterns, the indigo flames in the sky spelled out the characters "Guiyou"—the very year her father’s ship had sunk.
"Break the ice!"
As the Steel Whip shattered the final ice barrier, the granary doors burst open. Shen Xitang stepped onto an ice sled and glided inside, finding three thousand piculs of official salt stacked in a Seven Star formation, each bag topped with a gilded scale weight.
She pulled up a scale weight and threw it at the salt pile. The sulfur-salt burst into flames upon contact with the metal, but instead of ledgers, the tongues of fire revealed half a map of the *Nine Frontiers Defense*.
"A brilliant 'open road to distract, secret passage to attack'!" Xiao Heng’s Steel Whip coiled around a burning salt bag. "The Ministry of Works has actually hidden military defense maps inside official salt!"
Shen Xitang extinguished the flames; the pinholes along the edges of the remnant map suddenly caught her eye. Using the reflection from the ice on the granary roof, the pinholes projected a winding frontier route onto the salt wall. Beside one mountain pass, it was labeled "Renyin Year Reconstruction"—the very fortification works Xiao Heng had overseen last year.
"Look, Your Excellency." She placed the remnant map over the intertwined branch patterns of Xiao Heng’s Steel Whip. "The layout of these reconstructed arrow towers is identical to the structure of the Ministry of Works' 'Armillary Crossbow Platform'."
Three strikes of the watchman’s clapper sounded at the hour of the Dog. Shen Xitang wrapped her cloak tightly and slipped into the granary cellar. The Glazed Lamp held by Qingxing suddenly sparked, its light casting the hidden patterns of the granary's ledgers onto the wall. Following the "Fire-Washing Revelation Technique" recorded in the *Creation of Heavenly Works*, she held the ledger near the ice wall, and it revealed a secret account of the Ministry of War purchasing Wa copper three years ago.
"Miss! There’s a hidden door here!"
The scarred boatman chiseled through the cellar's north wall, revealing an ice tunnel slanting deep underground. Shen Xitang wedged a modified climbing pick into an ice crevice; the phosphorus powder on the pick’s head traced a ghostly blue path in the dark—the route of this tunnel perfectly coincided with the secret path marked on the *Nine Frontiers Defense Map*.
"Get the sulfur tubes!" She swung her climbing rope. "The end of this ice tunnel must be..."
A heaven-shaking explosion cut her off, the shockwave throwing everyone back. In the shattered ice, Shen Xitang felt a gilded medallion. The Big Dipper pattern on its surface was missing the Tianquan star—this seal matched the deployment tally Xiao Heng had lost the previous year perfectly.
"Miss Shen, quite the craft!"
From the depths of the ice cavern came the sound of clashing metal, and twenty armored warriors burst through the ice. Shen Xitang recognized them as the "Iron Pagodas" privately raised by the Ministry of Works; the wolf-teeth spikes at their joints glinted with the sulfur-blue characteristic of the Wa state. She snapped the Ice Silkworm Gloves from her wrists; the threads, soaked in naphtha, ignited into a wall of fire upon contact with the wind.
"Fall back to the Xun position!" Xiao Heng’s Steel Whip coiled around an Iron Pagoda’s ankle. "Their armor joints are at..."
Before he could finish, Shen Xitang’s Pear Blossom Rain Needle had pierced the seams of the armor. The steel needles, laden with arsenic-soaked ice shards, struck the warriors' kneecaps. As the first armored figure crashed to the ground, she caught a glimpse of the warrior's inner quilted armor—it was made from scraps of the "Skysining Brocade" exclusively supplied to the Shen family.
At the fifth watch, Shen Xitang stood before the charred granary. The remnant map in her hand, joined with Xiao Heng’s deployment tally, revealed a complete frontier layout. The location of the armory marked on the map was the "Huimin Granary," which the Ministry of Works had petitioned to build just last year.
"The Winter Solstice Grand Court Assembly is tomorrow." Xiao Heng shook the ice crystals from his cape. "Miss Shen, do you dare to face the Emperor and present this map?"
Shen Xitang pressed her Ice Silkworm Gloves against the remnant map, the threads forming seven distinct indentations. "I need twenty modified looms to weave the *Nine Frontiers Heavenly Works Map* within three days!"
On the twenty-second of the twelfth lunar month, in the freezing cold, the white marble steps before the Hall of Supreme Harmony were covered in a thin layer of frost, looking like a world of silver. Shen Xitang stood before the hall and unfurled a ten-foot-long tapestry, which glittered brilliantly in the morning sun.
Sunlight filtered through the warp and weft of the Ice Silkworm threads, projecting a dynamic image of the frontier onto the golden bricks of the hall, as if the borderlands thousands of miles away were being presented before everyone’s eyes. Just then, the hidden markers of the Ministry of Works suddenly appeared in the image, shocking everyone present.
However, more unexpectedly, an official from the Censorate suddenly rose in a fury, his sleeves hiding crossbow bolts, pointing directly at the Emperor on the dragon throne.
"Protect the Emperor!" With a shout, the palace guards sprang into action. Xiao Heng wielded his Steel Whip like a gust of wind, rushing toward the censor; the whip danced through the air and coiled around the man’s body.
In this moment of life and death, Shen Xitang quickly tore open the lining of the tapestry, and three thousand indigo-soaked copper nails flew out like rain, embedding themselves precisely into the palace pillars. As the nails embedded themselves, a clear line revealed itself upon the pillars—the very route of the weapon smuggling.
In his struggle, the censor tore his own court robes, revealing a Tiger Tally of the Ministry of Works tattooed on his chest. As the crowd looked on, they saw that this tally fit perfectly with the gap in the Armillary Secret Key; without a doubt, this censor was the mole for the Ministry of Works.
"A marvelous Heavenly Weaver indeed!" Seeing this, the Emperor stood up, clapping and showering Shen Xitang with praise for her wit and courage. He immediately issued a decree, promoting Shen Xitang to oversee the Imperial Textile Factory and bestowing upon her the Double Fish Tally in recognition of her meritorious service.
Shen Xitang bowed to give thanks, but she pondered deeply in her heart. When she caught sight of the newly carved intertwined branch pattern on Xiao Heng’s Steel Whip, she felt a jolt. The direction of those patterns was clearly an improved scheme for frontier military defense. She realized that this "Armillary Game" had only just reached the middle stage, with many more mysteries and challenges hidden ahead.