The rhythm of the forge was an iron heartbeat that refused to stop.
Clang. Turn. Clang. Turn.
The heavy wrought tongs in Pei Jing’s hands shook with every hammer blow, transmitting five thousand pounds of peak impact force straight up his wrist bones, along his radius and forearm bone, and directly into the shoulder socket of his shoulder.
A normal apprentice holding tongs under an eighteen-pound sledge would have suffered debilitating tenosynovitis within thirty minutes. The nonstop bone-shaking echo would cause tiny tears in the flexor retinaculum, swelling the wrist tunnel and inflaming the bone-skin lining of the forearm bones.
Pei Jing didn’t fight the shaking with rigid muscular pushback.
He engaged his Joint Manipulation and Python Tendon Stance.
His wrist and elbow joints remained slightly unlocked, suspended in an elastic, dynamic balance. Mo Tie’s sledge dropped onto the glowing hard dark metal billet. Then, Pei Jing allowed his shoulder joint to compress a tiny fraction of an inch into its socket, transferring seventy percent of the moving recoil downward through his broad back muscles, down the spinal erectors, and draining away it harmlessly through his heels into the granite floor.
The anvil took forty percent of the blow. The stone bedrock took thirty percent. The metal absorbed the rest.
On the anvil, the billet flattened, widening into a glowing orange tongue four inches wide and an inch thick.
“Chisel!” Mo Tie roared, his leathery face splattered with black charcoal soot.
Pei Jing released his left grip on the tongs, caught a hardened cold chisel from the anvil rack. Then he set its edge directly across the center of the glowing plate.
Mo Tie’s hammer swung down with clean, steady care.
Crack.
The chisel bit halfway through the steel.
Pei Jing tossed the chisel back into the water trough, took the tongs with both hands. Then he folded the glowing plate over itself like a thick leather wallet.
Sizzle.
He grabbed a handful of powdered borax and dry white quartz dust sand. It scattered it across the glowing screen.
The borax melted instantly upon contact with the eleven-hundred-degree steel. It formed a see-through, liquid glass flux that dissolved all iron oxide scale and shielded the seam from sky oxygen.
“Back in the throat!” Mo Tie barked.
Pei Jing thrust the folded billet into the white-hot core of the fire.
He moved back to the box bellows, working the twin hickory handles with his left hand for three minutes until the fire roared to yellow-white heat. Inside the firebed, the molten flux bubbled out of the seam. It allowed the virgin, unoxidized surfaces of the two steel plates to fuse at the core level.
Forge welding.
When the billet reached twelve hundred degrees. It glowed like a piece of the morning sun, Pei Jing drew it out and slammed it onto the anvil horn.
Mo Tie’s sledge hammered down in rapid, overlapping blows.
Clang-clang!
Liquid flux sprayed out in bright, sizzling droplets that struck the leather aprons and scorched the wooden rafters. Under the huge pressure of the hammer, the crystal-clear boundaries of the high-hard dark metal jacket and the hard steel core intermingled, their carbon atoms diffusing across the boundary until the seam ceased to exist.
One fold became two layers.
Two folds became four.
Four became eight.
By the fourth day of nonstop labor, the billet had been folded. It was drawn out, cut, and welded over eighty times.
The gross weight of the raw pig iron had dropped from one hundred and twenty pounds to barely thirty-five pounds. Over eighty pounds of metal had been sacrificed. Burned away as iron oxide scale, skimmed off as stone-glass melted rock waste, or chipped away as brittle flash.
What remained was a metal bar of unimaginable thickness.
Every fold tightly packed the crystal-clear grain of the steel, breaking down coarse ferrite crystals into tiny, linked fibers of pearlite and cementite, lined up along the lengthwise axis of the blade like the grain of an ancient hardwood tree.
During the short rest breaks between heating cycles, Pei Jing sat by the water chute, consuming massive quantities of high-connective tissue fuel.
He drank two quarts of thick broth brewed from stewed steer tendons, wild mountain ginger, dried wolfberry fruit, and three spoonfuls of rendered bear animal fat. The scalding broth tasted of sulfur, marrow, and rich fat oils.
A curious body phenomenon began to unfold within his skeletal frame.
Normally, the intake of high-calorie healing broths soaked only the muscular compartments and adipose tissue. But here, subjected to fourteen hours a day of brutal radiant forge heat and thousands of bone-shaking blast waves shaking through his arms, his internal breath flow shifted.
The blast waves created transient, sub-cold and exact micro-stresses along the outer-brain surfaces of his ulnae, radii, and collar bones.
The osteocytes within the bone matrix, stimulated by the pressure-sparking effect of repetitive clockwork loading, signaled for immediate stone settling. The packed fats, calcium, and connective tissue peptide chains from the bear animal fat broth didn’t linger in his stomach tract. They were drawn into his bone-skin tiny blood vessels like water into dry sponge.
Beneath his skin, his arm bones felt heavy, warm, and remarkably dense.
It was the first, unprompted body-energy foundation for the next martial realm: Bone Cleansing.
On the fifth afternoon, disaster threatened the forge.
Pei Jing had just drawn the billet from the fire for the one-hundred-and-twentieth fold. Mo Tie struck the first heavy flattening blow. Then, a dry, tearing sound echoed from the center of the bar.
Tsssk.
A jagged hairline fissure, half an inch deep, opened along the upper ridge of the hard dark metal cladding.
Mo Tie froze mid-swing, the sledge resting against his leather-wrapped shin. His single eye widened, his breath catching in his throat.
“Rotten luck,” the old smith cursed, spitting black spit into the dust. “A cold-shut. The anvil horn chilled the lower face before the hammer struck. The hard dark metal cooled below nine hundred degrees while the core was still hot. It’s cracked along the spine.”
Mo Tie tossed his hammer toward the scrap bin with a bitter snarl.
“Thirty hours of labor wasted. Once a high-hard dark metal billet cracks along the spine, you can’t weld it shut. The crack traps air. If you forge a blade with an internal air pocket, it will snap the first time it hits armor. We have to scrap it and start over with fresh billets.”
Pei Jing didn’t drop the tongs.
He held the glowing bar steady on the anvil, his eyes fixed on the fissure with tiny focus.
His Flesh Forging sense acuity and Tendon Elasticity gave him an intimate, tactile understanding of internal material stress. He felt the heat slope through the tongs. The lower face was five hundred degrees cooler than the top face, causing unequal heat contraction that pulled the crystal-clear lattice apart.
“The crack is only four tiny fractions of an inch deep,” Pei Jing said. His voice fully was calm. “The hard steel core hasn’t separated. It’s purely superficial shear on the hard dark metal skin.”
“It doesn’t matter how deep it’s!” Mo Tie roared. “The air is inside! If you hit it now, you drive the oxygen deeper into the core!”
“We don’t hit it with the sledge,” Pei Jing said.
He leaned forward, using a slender iron spatula to pack pure anhydrous borax powder directly into the open fissure until the white salt filled the crack like mortar.
“Put it back in the hearth,” Pei Jing commanded. “Raise the heat to thirteen hundred degrees. Let the borax liquefy and purge the trapped gas from the bottom up.”
Mo Tie stared at the youth in disbelief. “Thirteen hundred degrees? If you hold high-hard dark metal steel at thirteen hundred degrees, the hard dark metal boils out as gas! The whole bar will burn into a sponge!”
“Not if we submerge it in an oxygen-empty bed of carbonized pine charcoal,” Pei Jing replied. “We bury the billet fully under six inches of dense charcoal. The carbon monoxide air prevents surface rusting. Meanwhile, the liquid borax floats the oxide out of the root of the fissure.”
Mo Tie’s mouth opened, then slowly closed.
He was a master smith of the northern borders. But he had never heard a seventeen-year-old youth analyze metalworking heat laws with such cold, algebraic certainty.
“And if it burns?” Mo Tie asked, his single eye glinting.
“If it burns, I pay you twenty silver coins for your wasted coal and walk away,” Pei Jing said.
Mo Tie grunted. “Fair enough. Shovel the pine charcoal!”
They buried the glowing billet deep within a bed of seasoned, oxygen-starved pine charcoal. Pei Jing worked the bellows with measured, razor-sharp care. That kept the hearth at exactly twelve hundred and eighty degrees for twelve minutes.
Through the viewing port, they watched the white borax powder melt into a clear, bubbling glass, forcing tiny bubbles of trapped cold air and oxygen out of the fissure.
“Pull it!” Pei Jing called out.
Mo Tie dragged the billet out with the tongs.
The fissure was glowing white, filled with liquid borax flux.
Instead of the eighteen-pound sledge, Pei Jing grabbed a three-pound cross-peen hammer from the rack. He stepped to the anvil, delivering dozens of rapid, light, angled taps along the lips of the fissure, working from the closed root toward the open end like a seamstress smoothing a silk seam.
Tink-tink-tink.
Under the gentle, aimed pressure, the molten flux was squeezed out of the joint, spilling onto the anvil in a clear bead. The ductile hard dark metal crystals flowed together, fusing seamlessly across the tiny gap.
Within ninety seconds, the fissure was gone.
The surface of the spine was smooth, nonstop, and unbroken.
Mo Tie leaned over the anvil, examining the metal with a magnifying lens of ground rock crystal.
Not a seam remained. Not a hairline fault.
The old smith slowly straightened his back. He looked at Pei Jing as if seeing him for the first time.
“You’re not a clerk,” Mo Tie murmured, his voice hushed with genuine awe. “You’re a demon with an anvil.”
“I’m an accountant,” Pei Jing replied, setting the peen hammer down. “And waste is an unacceptable debt.”
He wiped sweat from his jaw with his sleeve. Then he stepped to the tool bench where he had laid the Black Mountain Whetstone. A splash of water from the cool tub wet the dark stone as he ran his thumb across its dished belly. That let the cold stone steady his pulse before the next round of hammering.
In his vision, the monospace ledger lit up with a satisfying click:
Mo Tie hefted his great sledge once more, a fierce, wolfish grin spreading across his soot-blackened face.
“One hundred and twenty folds done! One hundred and eighty to go! Let’s make this blade sing!”