Part 1 - Min Mu-jil's Relatively Peaceful Days
Before long, it was already June 10, 1401. Time was flying by faster than expected. In high spirits, Min Mu-jil arrived at the Bureau of Military Weapons as usual to discuss future improvements to cannons. That's when Yi Cheon-u spoke up.
"My lord, you're in a good mood today."
"Wouldn't you be? All those memorials criticizing us have vanished."
Yi Cheon-u replied, "On the contrary, memorials are coming in calling for even greater strengthening."
All the officials burst into laughter. Indeed, ever since the recent demonstration of the fire chariot, complaints about the bureau's inefficient operations had completely disappeared. Instead, petitions poured in demanding more funding.
During the demonstration, flames had erupted from the fire chariot as countless arrows launched in unison. Everyone gasped in awe. But when those arrows struck their targets at incredible speed, detonating the secondary explosives attached to the divine fire lances and sending shrapnel and flames exploding outward, the crowd fell silent. Their faces said it all: What have we just witnessed?
Min Mu-jil had even shown them adjusting the angle for different ranges, proving how the effective distance varied with elevation. The officials were thrilled, and from that day on, no one dared criticize the bureau's operations.
To top it off, tests of the new quicklime production yielded over eight times the gunpowder output of previous methods. Now, memorials demanded outright expansion of the bureau. Some officials went so far as to argue that Joseon's path forward lay in advancing gunpowder weapons, submitting incredibly detailed proposals. One even suggested recruiting specialized troops trained exclusively in gunpowder armaments for the military. In short, reorganize the army around gunpowder weapons—just as Min Mu-jil had hoped.
The sight of that fire chariot in action really hits different. Of course, there was a downside. Some wanted mass production for deployment to the northern borders. That idea was shot down, though. Before the demonstration, Min Mu-jil had explained the pros and cons to Yi Bang-won, who ordered only about a hundred units—no need for mass production. It made sense from a cost-effectiveness standpoint. He also commanded development of superior gunpowder weapons.
Min Mu-jil agreed. Honestly, the fire chariot's main purpose was buying time—time to develop gunpowder weapons without interference. It served dual roles: stalling tactics suited to the kingdom's terrain and a proven concept, thanks to Choe Museon, father of Choe Hae-san, who had already pioneered it. Easy enough to build on.
Anyway, back to discussing future cannons. That's when Yi Cheon-u and Choe Hae-san's opinions diverged. Yi Cheon-u pushed for personal handheld firearms; Choe Hae-san wanted bigger, more powerful cannons. Both were needed, but Min Mu-jil sided with Yi Cheon-u for now.
Handguns like matchlocks would be convenient. "Just don't think about miniaturizing cannons. We don't have the copper for that. Something like a crossbow you can fire personally would be ideal."
"What do you mean, my lord?"
"I'll sketch the design I have in mind. Judge it for yourself."
"Yes, my lord."
Min Mu-jil picked up his brush and drew a rough matchlock musket. He showed it to Yi Cheon-u.
"My lord, may I speak frankly?"
"Of course. Be honest."
As if you haven't always been straight with me. Yi Cheon-u had even called out the fire chariot for wasting too much gunpowder right after its development—a brutally factual critique.
"I understand what you're going for, but it needs more precise engineering. As it is, no amount of pushing the artisans will produce it. If you could draw it as detailed as the fire chariot plans, I'd be grateful."
He's basically begging: don't half-ass it, make it meticulous.
"Got it. I'll work on it."
"Still, a handheld firearm like this would definitely be practical."
Guess I'll have to dig deep into my past-life memories.Should've studied matchlock designs if I knew I'd end up in another world. Not that reincarnation was on my bingo card.
After wrapping up the debates, Min Mu-jil returned home for the first time in ages. There, surprisingly, was Jang Yeong-sil.
"My lord, you've returned."
"Indeed. It's been a while. How have you been?"
"Thanks to you, my lord, I've been well."
In that moment, it hit him: This kid could do it. With the generous funding Min Mu-jil provided, Jang Yeong-sil's crafting skills had skyrocketed. His jewelry was all the rage lately.
Genius plus unlimited budget equals results. Even the fire chariot's cart benefited from his input—when Min Mu-jil showed him the designs, Jang suggested a better frame shape.
Why not bring him into the bureau? "Yeong-sil, how old are you now?"
"Sixteen."
"Ever thought about working as a technician at the Bureau of Military Weapons? I'll pay handsomely."
"Could a kid like me really...?"
"Yeong-sil, have you forgotten who I am? If I say so, it's done."
Min Mu-jil wasn't cowering from Yi Bang-won's purges out of fear alone. As the king's brother-in-law, Geumjeongsa and Defense Command Commissioner, Second-Class Meritorious Retainer of the Jeongsa, First-Class Left Wing Meritorious Retainer, and bearer of the Yeoseonggun military title, few things in Joseon were impossible for him.
Jang Yeong-sil bowed deeply. "I can never repay your grace, my lord. Thank you."
"Help develop great weapons, and that's repayment enough. I'll recommend you tomorrow—start the day after. I'll send clothes over."
"Yes, my lord. Truly, thank you."
Time to put Jang Yeong-sil to work for real.
Relaxing at home later, a messenger arrived from the Prince Chungnyeong Office. Yi Seong-gye summoned him. That guy never lets me rest. Off to Soyosan Min Mu-jil went.
Entering the temporary palace, Yi Seong-gye greeted him. "You've come."
"Yes, Your Highness TaeSangWang."
Min Mu-jil served braised short ribs, Yi Seong-gye's favorite, and he devoured them as always.
"Bring something new next time. I'm tired of this."
Stuffing his face like that and complaining.
"That fire chariot you showed off—well made."
Oh? Even Yi Seong-gye approves.
"But full of problems. Gunpowder consumption is way too high at a glance."
As expected from the undefeated general.
"Why not improve cannons instead? I'd have approved more. Sambong would have."
Just nitpicking. Mentioning Jeong Do-jeon confirmed it. Time for a counterpunch—Min Mu-jil couldn't just take it.
"But it uses less copper, doesn't it? Makes it a good weapon. Copper-heavy ones would be hard to procure. Or maybe not so hard."
"Now you're teasing me, you brat. Incorrigible."
Min Mu-jil brought up copper for one reason. Superior cannons required massive amounts for mass production. And Joseon had an easy source: melt down temple bells. Nations worldwide did it for defense. In this anti-Buddhist kingdom, they'd seize the chance, stripping temples with glee.
Min Mu-jil had called it out; Yi Seong-gye got the point.
"You always know how to twist the knife. Brat."
"My apologies."
"Apologize with new food next time."
"Yes, Your Highness."
"Seeing you reminds me of someone else."
Not Jeong Do-jeon, given the tone.
"Yeom Heung-bang, before he fell. He was impressive back then."
"I've heard."
"Makes sense—your father and Yeom were old pals. Seok-rin too."
Pre-corruption Yeom Heung-bang deserved praise; he was exceptional. Min Mu-jil knew because, as Yi Seong-gye said, his father, Yeom, and Seong Seok-rin were exam classmates. Father stayed close until the fall, then cut ties—but he'd lament the tragedy now and then.
Still, dragging Yeom out felt like a jab. If praise, he'd mention Jeong Mong-ju, but never.
"Yeom was soft on Buddhism too. These Joseon scholars hate it too much. Even your idea was called too weak."
Ah, that. Recently, Yi Bang-won restarted anti-Buddhist policies, starting with temple troops as Goryeo remnants—per Min Mu-jil's mediation. Yi Seong-gye, Goryeo's conqueror, stayed quiet. But calls for more demanded escalation.
"Push further—burn temples—and they'll starve us out like before. Tell Bang-won that."
"Yes, Your Highness TaeSangWang."
"How's the Ming civil war?"
Yi Seong-gye obsessed over it.
"Chu Wang's dead now too. Official cause: suicide. But from what I gather, forced. Half the Feudal Kings gone."
"Good news. And Zhu Che?"
"Reorganizing, winning in Shandong—but stuck there."
"Incomprehensible. Is Zhu Che after land? The throne? After losing at Dongchang, only one path: straight to Nanjing. Why not?"
Yi Seong-gye sees it clear as day.
"I agree."
"You know strategy well. Ming'll sort itself. If Zhu Yunwen thinks straight, he'll hold."
That's the problem—he doesn't. Current reports cast doubt on a Nanjing push. Post-Dongchang losses crippled Zhu Che, but Zhu Yunwen made sound calls—like resending Seo Hwi-jo to Shandong, garrisoned at Guando. To strike Nanjing, Zhu Che must cross and pass there.
Whose idea? Zhu Yunwen's circle lacks tactical skill—scholars good at grand strategy, weak on details. Not Cheol Hyeon. Did Seo Hwi-jo suggest it? Or Je Tae influence him? Unintended butterfly effect from prodding Je Tae.
Anyway, the Jingnan Rebellion deviated from history. Good—prolonged war suited Min Mu-jil. With kings suicided, Zhu Che wouldn't surrender; it'd drag on.
If it stays this way.
"Go now. New food next time."
"Yes, Your Highness TaeSangWang."
Leaving Soyosan, Min Mu-jil reflected: Yi Seong-gye's nagging was tolerable. Ming issues aside, his clan was quiet. Father enjoyed leisure, free of power lust. Min Mu-gu fine for now. Shockingly, Yi Bang-won curbed his womanizing, delighting Min Da-yeon. But it'd erupt eventually—zero chance he'd quit.
Wonder how it'll blow up.
Back at the office, trouble brewed: the royal marriage issue. Triggered by envoys from Ming, where Hwang Ja-jing asked about wedding Princess Bokyeong. Bold move—urging Joseon to propose, positioning himself to endorse and regain favor.
Yi Bang-won refused. He wanted Zhu Yunwen's daughter, not Bokyeong's—a secret among him, Min Mu-jil, and Min Da-yeon. With Zhu Yunwen expecting a son, that ship's sailed. Hwang Ja-jing's loss.
Late—time to head home. Arriving, he saw a crowd out front.
"Wife, what's this?"
"Well, husband... They want to discuss the royal marriage with you."
Why the fuck me? Trying to get me killed? Debating the crown prince's marriage—not with the king, but me? After Yi Bang-won refused?
They were chased off. Overhearing: they insisted marriage vital for Joseon, targeting Min Mu-jil's Ming ties to push it through.
Fuck, this backfired hard. All that diplomacy to dodge purges and build Joseon—now this? Life's bullshit at peak levels.
But it wasn't over. Father and Min Mu-gu got visitors too.