Forging the Black Thunder Cannon
Mobile cannons. *** Of course, if a person grips the drill and pushes, the hole ends up crooked. So instead, you mount it firmly on a cart built over iron rails on the ground, then slowly turn a massive screw from behind—like the ones used in perforation techniques. It'll bore slowly, but straight as an arrow, letting you craft a proper barrel.
Just building the water-powered drill took three weeks, and crafting each drill bit added another week. In a full month, we barely managed ten machines. Complaints were inevitable, of course. But I applied some financial therapy to smooth things over. As a bonus, I paired off the remaining unmarried Bulgarian women with them to spark some rivalry. I even arranged marriages for the single men among the artisans.
These days in Goryeo—excluding the elite Byeolcho Army—artisans rank as top-tier jobs. It's thanks to that status. They take pride in it, but when they slack off, a good scolding is the least they deserve.
Next came the actual casting. Cooling took a full week. Drilling the bore? Another three or four days. The waterwheels never sleep, running three shifts around the clock, splashing water nonstop as they grind away. That boring process alone eats up three or four days. It's brute force at its crudest, so the pace is glacial. Who could've guessed a single water-powered setup could produce something like this?
Once the cannon's made, the production line cranks out one every two weeks after setup. But there's a catch: this thing's so revolutionary, it demands equally advanced components. For precise aiming, you need screw handles to fine-tune the elevation. So how do you make screws?
Take a cylindrical iron rod and wrap it with paper cut into a right triangle. The hypotenuse spirals up around the rod. Trace that line with a chisel—that's your screw thread blueprint. Now summon the first screw master.
"Alright, here's your task: chisel the iron along that line with the chisel."
"You mean carve it like this?"
"Then quench the shavings to forge tough tool steel."
"Heh, I've sharpened blades before, but carving iron like this? First time for everything."
The artisans sighed in resignation by now, but the financial therapy helped. This master screw becomes the original tap for replicating more. We named it "deulmot"—literally, a "twist-driven nail."
Of course, you need nuts too, not just bolts. Forge a block of brass or soft iron with a central hole. Force the master screw in. Steel screw meets soft brass; brute force twists it right through. Human muscle power suffices.
Now for the screw-cutting lathe: split a long rod into an axle, attach the master screw, and use that to drive the machine. Run it on water power for mass production. That's the screw-elevation mechanism for this cannon.
We paused there and finished the cannon.
"Whoa, it's pitch black."
"Steel construction'll do that."
Steel means black as night, no helping it.
"So, what's it called?"
"Hmm. Black barrel, earth-shaking thunder—how about Black Thunder Cannon?"
No way I'm slapping on some lame historical label like "total tube." Screw those waterlogged Joseon names. Call it a cannon, bold and proud.
And the Black Thunder Cannon's performance? Insane. Bore around 110-120mm, barrel 2.5 meters long. Weight about 800kg bare, 1.5 tons with the gun carriage. The carriage—wheeled platform for the gun—weighs 700kg itself.
Why so heavy? To absorb the recoil when it fires. Building the carriage means reinforcing oak with iron plates and casting iron wheels. How'd I calculate it? Length's a guesstimate, weight felt right. Needs at least four horses to tow, so yeah.
Old fire lances sat fixed in wooden frames—immobile. Wheels change that: horses pull at running speed. Retreat from approaching foes, pursue and blast.
To anchor: drive wedge screws into the ground through carriage holes. The screw tip braces the cannon's breech. Turn the handle right, screw rises, lifts the breech, drops the muzzle. Left, and it reverses. No more wedging logs for angle—simple.
Now loading: old fire lances meant powder, ram, shot—slow as hell. I introduced paper cartridges. Pre-pack powder and shot in oil-soaked paper, shove and fire. Expert crews hit three rounds a minute.
Hanji paper's too tough—doesn't tear clean, ash clogs the bore. But use the grain right, and it rips perfectly. Soak tough hanji in thick limewater slurry, dry stiff. Coat the outside thin with oil and beeswax. Done.
Problem: first live-fire test.
"You made us bust our asses for this. Mass production'll take forever—if it sucks, I'll feel robbed."
I'd tasked Kim Jun with it after ages. Gave him full blueprints, so no issues.
"Fire!"
Boom!
"Damn, it flies far."
"That's random aim. Precision fire cuts range but boosts accuracy."
Scarier still: the round ball doesn't just bury in dirt—it ricochets like skipping stones, skimming enemy lines. Casualties explode—that's ricochet fire. Post-test, cavalry confirmed skips along the shot path. Range matched calcs too.
"Takes forever to make, but it'll hurt the enemy bad."
"Yep. If Mongol horse dare close in, load grapeshot and shred 'em."
"Gotta ramp production."
"Right. Casting's quick enough, anyway."
Tough to build, but water power handles it. Compare to old sphere lances: 600-800m max vs. Black Thunder's 1.8-2km, effective 200m vs. 800-1,000m. Pinpoint vs. spray-and-pray. And mobile: wheels track foes, hit-and-run like Mongol tactics, but with cannons.
"But seriously—this can't be built anywhere else, right?"
"Nope. Even grasping the need, this tech's generations ahead."
Put it like this: normal history means trial-and-error from scratch, needing some spark. I know the path, so this happens.
"Incredible."
"Credit the mountain spirit."
Yeah, the spirit's the genius. Right? That old man's fault—can't die, reincarnation's iffy, so grind modern tech.
"We absolutely can't lose the Taejah River."
"True. Lose this water-powered miracle hub, and Goryeo's power craters."
Water got us here with 6 million souls. But yeah, contingency on mainland. Damn, revolutionary stuff. Potatoes and corn boost food too—feed easy. Population math: old 10 farmers for 10 eaters? Now 3 feed 10. Rest funnels to Yodong industry—synergy city.
Northern refugees do grunt work; women spin, make cartridges, pack powder. Delicate tasks. Women freed from housework power the factories. Key.
"With these weapons, we could take not just Mongols—maybe even the Central Plains?"
Could. Jin falls easy, push to Song. No Mongol combat prowess, but overwhelming arms. Song's matchlocks train under our Byeolcho officers—civilian rule, weak military. Smash 'em.
But aftermath?
"Possible, sure. But in centuries, Goryeo folk assimilate as minority. Trouble."
Even lenient, to endure without absorption? Yuan-style terror rule. Mongols had to oppress to preserve identity. Sparks Han backlash—chased north like Northern Yuan. Bad end either way.
I'm a nationalist. Won't let this become China. Many built empires here, absorbed by Han masses. Can't ignore that manpower. We absorb others to grow: Jurchens (Malgal heirs, old Goguryeo), maybe Japanese (Baekje ties, immigrants). Full peninsula. Pretty map.
No China fixation. Secure pop here, sell advanced goods there—suck their wealth. Land? Sakhalin, Kamchatka, Alaska. Millennium secured. Descendants spread to Maple Island cheats. No Joseon-style China bootlicking, mocked as vassal. Proud nation, envied by all. Power's mine; task too.
"Truly visionary. So thoughtful."
"Praise more. Easy serving a boss like me?"
Praise puffs people up. ***
Jin's plundering birthed pirates in China. Song holds—Goryeo arms help defense amid chaos. But displaced bandits and hill robbers got stripped by Song troops and Jin raiders. Where do they go? The sea.
Border chaos let them steal Yangtze boats, flee seaward. Targets: Goryeo trade ships, booming, selling luxuries to Song. Hesitant at first, but time emboldened—big scores.
"Goryeo bastards tough with those new weapons."
"Just ragged ships, no real arms."
"Hit 'em big this time."
They assembled a massive pirate fleet. Song's numbers meant hordes of pirates. Spotting Goryeo's huge trade convoy, they swarmed.
"What's that ship? Huge!"
"Ship's a ship—take it!"
"Aye!"
Moths to flame, charging the cannon-armed keels ships.
Boom-crash-bang!
Cannon fire sank them instantly. Not one unscathed. All wrecked or afloat hulks.
Trade ships weren't easy either. Rifle-trained crews shot back at grappling pirates. Pirates retreated; cannons reloaded, fired again.
"What the hell!"
"No retreat—we're dead anyway! Charge!"
Boarders met grapeshot, tumbling to Dragon Palace. Those reaching keels? Northern vets—Khitan, Jurchen warriors who'd fought Mongols.
"Seasick as hell, and these Han pigs think they can board here?!"
Blades flashed; pirates sliced to ribbons.