Crafting the Carriage Shock Absorber
My daily life had been completely upended. All day long, I faced nothing but the roaring heat of the blazing furnace, the glowing red-hot iron chunks, and the heavy thud of the hammer striking down.
True to his word, Yeom Cheol didn't make me do any menial chores. Instead, he hammered into me—like carving the basics into my very bones—the blacksmithing fundamentals he'd honed over a lifetime: how to gauge iron's temperature by eye, how to adjust the bellows to stoke the furnace's core heat higher.
"Look at the flame's color! That's when the iron softens most. Linger a second too long and it'll burn; heat it too little and your hammer bounces back, snapping your wrist!"
Yeom Cheol's thunderous commands echoed through the forge dozens of times a day. I absorbed his teachings silently, with terrifying focus, like a sponge soaking up water.
Then one morning...
"Inspect the cart—hurry! The young lady's touring the farms and textile workshops on the outskirts of Xu Province today!"
The escort captain's bellow sent the merchant guild's courtyard buzzing. At its center waited the top-grade carriage for Mi So-jeo: a massive thing framed in sturdy, glossy rosewood, its exterior draped in lavish silk. Four strapping white horses pulled what was less a vehicle than a mobile fortress, symbolizing the Mi merchant clan's wealth and power as Xu Province's premier trading house.
Yeom Cheol and I were summoned to check the iron fittings on the wheels and the axles.
"Axle's fine. Nails are solidly in place."
Yeom Cheol thumped the carriage wheel with his thick hand and nodded. I silently scrutinized the wheel and the undercarriage structure it connected to. The large, heavy wooden wheels were rimmed with thick iron tires for durability. The stout wooden axle supporting them was rigidly fixed to the carriage body below with iron nails and ropes—unyielding and stiff.
Brutally primitive design.
My brow furrowed slightly. Compared to modern cars or even carts, this era's carriages had a fatal flaw: no suspension whatsoever. Every jolt from the ground hit the rigidly mounted wooden axle and transmitted straight to the carriage body—and its passengers.
"The young lady's coming!"
With the guards' shout, Mi So-jeo emerged from her pavilion, elegant in a simple purple silk robe, supported by her maid. She moved with her usual refined grace, but a faint shadow creased her brow as she boarded.
The carriage lurched into motion. Xu Province city's roads were packed dirt topped with flat stones—seemingly smooth, but with misaligned gaps making the surface brutally uneven.
Thud!Clunk!Crunch! Each time the iron-rimmed wooden wheels hit a bump, a horrific, dull clamor erupted, the massive carriage body bucking wildly up and down. Through the silk window curtain, Mi So-jeo's silhouette swayed precariously, unable to brace against the shocks.
"Slow down! The young lady's uncomfortable!"
The escort captain, walking alongside, snapped irritably at the driver. Even when the coachman reined in to a walking pace, the sharp vibrations from the wheels cresting stones persisted unabated.
The carriage halted. The curtain parted, revealing Mi So-jeo's pale face. She clutched her mouth like she was nauseous, breathing raggedly.
"Young lady, are you all right? The road's in terrible shape."
The captain rushed over, bowing low. Mi So-jeo waved him off weakly, forcing composure through the pain.
"It's my frail body—don't blame the driver. We have a full schedule today; I'll endure the bumps. Let's go."
She shut the window resolutely, but as the carriage rolled again, faint groans leaked through. For a noble lady to suffer such torturous jolts all day on patrol was nothing short of torment. I stared piercingly at the receding carriage, especially the axle bouncing relentlessly up and down.
Just like an old man's knee with worn-out cartilage. Bone grinding on bone, crushing nerves—that agony was familiar from hauling heavy loads in my modern life until my joints ground down. The carriage lacked that flexible 'cartilage' between the shock-absorbing wheels and the passenger compartment to cushion and disperse impacts.
"What're you staring at like an idiot, Aman?"
Yeom Cheol thwacked my back.
"Master. The carriage vibrations are too severe. Even setting aside the strain on the young lady, that wooden axle will fatigue and snap mid-journey someday."
Yeom Cheol snorted dismissively at my observation.
"Stating the obvious, boy. Wooden wheels with iron rims on stone roads—which carriage doesn't jolt? Even the emperor's imperial carriage layers thick silk cushions to soften it, but no magic stops the shake. Iron and wood are hard and rigid by nature."
Iron and wood were hard. That was this era's common sense. But my modern upbringing recalled hazy knowledge of tempering steel to make it springy like rubber bands or coils.
Quench red-hot steel in water, and it hardens glass-like. But reheat that brittle steel gently at lower temperatures to relieve internal stresses, and it gains resilient 'elasticity'—bending without breaking, snapping back to shape. The principle of leaf springs.
"Master. What if iron were both hard and flexible enough to bend like a bow and absorb shocks?"
"What? Iron bending like a bow? Nonsense. A thin sword blade, maybe—but a thick chunk bearing a carriage's weight going all floppy? That's just soft shit-iron. One hit and it'd stay bent or snap. Quit dreaming and stoke the furnace."
Yeom Cheol tsked and stomped back inside. I smirked faintly and headed to the scrap pile in the courtyard corner.
No point explaining—they wouldn't get it. I'd have to show results with my eyes. I scoured the heap, pocketing four thick, long leftover iron plates from wheel rims, hiding them secretly under my bunk in the side room.
That night. With the guild dark and silent, in the pitch-black side room with windows shuttered tight, I sat and laid out the thick plates on my lap.
Forging deadly swords to boost strength mattered, but imprinting my value on the guild's real power, Mi So-jeo, was the ultimate investment for survival and building influence.
"Status Window."
Mana: 6
Mana at 6. The Subspace Forge, evolved to level 2 yesterday, now lasted 6 minutes. Just one extra minute, but priceless for adding the delicate 'tempering' step after quenching.
"Subspace Opening."
Shooo—! The familiar chill sucked 5 mana from my dantian, vision warping roughly.
Flash. Blinking, I stood in my level 2 forge, greeted by hard clay floors and the steel anvil.
Subspace Forge (Blacksmith Shop) has been created.
Duration: 6 minutes
A red timer counted down in my retina's corner. No time to waste—I lit the furnace, shoving the thick plates into the charcoal pile with both hands.
Hiiiiss—! I pumped the bellows furiously. Stamina 52 kept my breathing steady and rhythmic.
Remaining Time: 04:30
Plates glowing cherry-red, I tonged them out, stacking on the steel anvil.
"Hup!"
Clang!! Clang!! Kaaang—!! Heavy hammer blows rang out. The level 2 steel anvil—unlike the old cast-iron one sunk in dirt—rebounded perfectly, channeling my full force into the metal for maximum efficiency.
Today, no lethal blade. I forged a 'shock link' like human cartilage, to fit between carriage frame and axle.
I hammered out impurities, shaping the thick plates into long, flat oval hoops (interlocking C-shapes), stacking layers into a thick spring bundle.
Remaining Time: 02:10
Form set, I plunged the glowing bundle into the water trough.
Chiiiii—!! Steam billowed as steel contracted sharply, hardening glass-tough. Quenching done. But stopping here? It'd shatter on the first bump. I eyed the timer.
Remaining Time: 01:45
Precious extra minute from more mana. I tonged the blackened bundle—not to the furnace core, but the charcoal's gentle edge. Eyes wide, I obsessed over surface color shifts: cold steel warming to pale yellow, deepening to brown, then subtle purple-blue haze!
"Now!"
Remaining Time: 00:30
Tongs snatched, plates yanked. Not water—into the new oil vat (level 2 perk) for slow cooling. Internal stresses softened in the gentle heat, iron crystals bonding flexibly. Tempering complete.
Remaining Time: 00:08
From the oil: an unremarkable stack of thick, black oval-hooped plates. But upright on the anvil, I smashed down full force.
Kaaang—! Miracle. The bundle that should've crumpled or snapped squished elastically—then ping! vibrated back to perfect oval shape. Success. Resilient artificial cartilage from hard steel—the Three Kingdoms' first leaf spring shock absorber.
Remaining Time: 00:02
Crude Leaf Spring Shock Absorber (F-rank) completed.
F-rank Blacksmith experience gained.
No stat-up messages. But I wasn't disappointed—stats weren't the goal.
Subspace maintenance time has ended.
Flash. Eyes open: quiet side room again. In my hands, two heavy leaf spring shock absorbers, oily and cool. In the dark, I smiled with satisfaction.