Teachings
The Mongol forces they could send to Goryeo numbered at most 30,000 to 40,000. If they clashed in close combat against our overwhelming numbers and firepower, only for 10,000 to 20,000 cavalry to stab in from behind—could the Mongols even endure it?
"Gathering up to 10,000 for this so-called Iron Cannon Byeolcho, eh? We've been supplementing with quite a few Jurchens defecting from Jin lately, but is it really worth pulling together numbers like this? If we lose the war, Goryeo's done for."
Exactly. It's a one-shot gamble. We'd have to scrape together every able-bodied young man who could fight from across the entire country.
"Every time the iron cannons spew fire and roar, the charging cavalry will take the hit. No way around it if we want to smash them. And you should put out word near the border—preferential treatment for any Jin technicians, from Dongjin or wherever—and bring them over."
We couldn't pin everything on Song merchants. Absorbing Jin refugees wasn't a bad idea, just like how Ugaha had surrendered to us. Our population needed to top five million. Right now, the household registers barely cleared three million. Song had over 100 million at its peak, Southern Song around 80 million, and Jin hit 56 million back in 1207—thanks mostly to absorbing Han Chinese, sure, but Goryeo was still pitifully small by comparison.
Population meant wealth. National power. At best, Goryeo scraped by with three million. Low numbers forced us into one decisive battle every time, and we had to win it. If we'd lost the Gwiju Great Victory, Goryeo might've ended up a Liao puppet state.
We had to maximize population growth. Ramp up birth rates. Absorb anyone worth taking. Jin had the bodies, but mostly Han. Only the upper crust were true Jurchens—and even their numbers fell short of Goryeo's. Pulling in those Jurchens would give us leverage over Manchuria too. Perfect timing, with the Jurchens there fractured into factions. Win the war against the Mongols, and Manchuria wouldn't just be a pipe dream.
"You don't act like a daughter at all. So, where do you want to set the battlefield?"
"The Gwiju plains would have strong symbolic value, wouldn't they?"
Goryeo's strategy was straightforward: the northwest fortresses bought time, while the central army gathered in the capital and marched north to crush the enemy—worn down and pinned fighting those garrisons. Which meant picking the right spot for the clash.
Gwiju. It had shone in the First Mongol Invasion too. Kim Gyeongson had plugged it tight; the Mongols never breached the walls. What if we rewrote history right there? Crush the army of the world-conquering Mongol Empire on the very site of the Gwiju Great Victory. The Choe name would echo beyond Goryeo, all the way to the Central Plains.
"Lose at Gwiju, and it's straight to Seogyeong. Pushed from Seogyeong, and Gaegyeong's next. No defensive lines in between. If we fight, we must win."
The map made it clear: past Seogyeong, and we're screwed. Not necessarily. No need to occupy Seogyeong at all. Look at the Goryeo-Liao wars. Liao couldn't take it, so they bypassed straight for Gaegyeong—cue King Hyeonjong's flight.
A loss at Gwiju meant slipping right back into the original timeline's Mongol invasions. So I handed over the diagram of the iron cannon wagon fort formation I'd slaved over. If it came from the mountain spirit, even Father couldn't refuse.
"Truth is, the mountain spirit came to me last night. Said if we're fighting the Mongols, do it like this."
"Iron Cannon Wagon Fort Formation."
"Once Mongol cavalry sets foot in Goryeo, they can't drag the war out. It'll be quick and decisive. They'll hunt our main army, smash it, then push south. Nothing crushes morale like shattering the enemy's core force."
Or else go for the direct-capital strat—abandon every other fortress and beeline for Gaegyeong. Like Sobaeap in the Third Goryeo-Liao War. Balhae fell to that. Centuries later, the Qing rode straight down for King Injo's head.
But the Mongols would want a grand showdown first, to break our spirit and force surrender. We needed a resounding win in the First Invasion.
"Let's clash properly at Gwiju."
The issue? In the actual First Invasion, Goryeo's three armies smashed the Mongols in open field battle at Dongsunryeong. A genuine field victory. Goryeo could handle pitched battles. The problem came later at Anbuk Fortress, where one army got wiped—tipping the scales to the Mongols.
"The spot might shift with circumstances, but that's usually best."
"Thorough, aren't you."
Not just Gwiju—we'd need to scout other viable sites. Hold out at Gwiju Castle while marching the central army north. Get lucky and plug them at Hamsinjin, and we could settle it right on the border.
Fighting at Gwiju meant heavy losses for the Mongols just getting there. Prep fast enough, and we could force the issue at Hamsinjin. Plenty of time left, though.
"Once war erupts, we'll have to yield the stone fortress beyond the Amnok River."
That fortress past the Amnok—where Kim Huija marched to subdue Ugaha in history, only for him to surrender and hand it over. Practically our border outpost.
But it'd fall to the Mongols soon enough. Enemy entry into Goryeo proper was a given.
"Unless we're making a do-or-die stand on the Amnok, we have to lure them in. Northwest garrisons hold the line while we duke it out at Gwiju."
"Your eye for this is spot-on."
The Choe regime caught endless flak for bungling Mongol relations, but Father was a seasoned politician and warrior. He had the vision.
"Yes. Doesn't this make me the perfect successor?"
"Successor, hm? Yeah. Way better than Yakseon."
Comparing me to Kim Yakseon? Come to think of it, what was that guy up to lately? Probably screwing around with women again. Never met him myself—no need to care. Marriage off the table, he was out of the successor running. Was supposed to hand it off through a son-in-law, but that wasn't simple.
"I've been looking after my little brothers lately too."
"That Manjong and Manjeon. Think those boys will shape up, from your view?"
Honestly? Doubtful. I wasn't babysitting them daily, but sister-worshippers? Obvious.
"What they want is Father's love. Both have their lowly-born mothers burned into their hearts. Don't push them away too far, Father."
"Hm."
He did see them as his kids, in his way. Goryeo society's limits kept him from embracing them fully. Or maybe he wanted distance from their "base blood."
"Comfort them as their father. And bestow proper names."
"Names? What kind?"
"Separate names as proof they're Father's sons—they'd love that."
History gave Choi Hang to Manjeon; something similar for Manjong. A fresh start, in name.
"Hm, I'll think on it. Bestowing names could signal I'm grooming them as heirs."
"It would?"
Would it? Thinking now, yeah.
Naming Manjong and Manjeon treated them as near-legitimate sons. How would Dobang or the officials react? Royalists might wedge in, stirring division.
"If you want my seat, you'll have to shed affection."
"Affection?"
Sudden gravity. What was this?
"Yes. You're a woman. A woman inheriting the Gyojungbyeolgam seat. Dobang. You grasp what that means?"
I did. A woman claiming power. Goryeo was open to women, but successors? Males first. I'd have to grind twice—no, ten times harder. Earn the generals' nod in this body.
But Father's tone felt... different.
"What does it mean, exactly?"
"Goryeo's progressive with women, sure—but heirs are still men's domain. Give those boys new names, treat 'em like legit sons, and even if they balk, others won't let it lie."
"They wouldn't?"
Made sense. Military regime meant men in charge. Power-hungry types would flock to Manjong and Manjeon. And there I was, a woman; them, men. Practically heirs already.
"Your little uncle eyed my spot—ended up exiled. Your grandfather, the Eunmun Sangguk, killed his own brother. Get the picture?"
"What are you saying?"
Forcing me to face ugly truths. A chill slithered down my spine unbidden.
Born a power-family daughter, yet overreaching for the throne—felt like staring down something forbidden.
"You're my daughter. Blood of Choi U. If you gun for my succession, you'll have to cut those two down harder than I or my father ever did. Think a woman's body earns warriors' respect easily?"
Me, kill them?
"How can you say that?"
Terrifying words. Father was laying bare the brutal world.
He pressed on, shaking my reason.
"That's reality. Dobang already knows your name. To claim this unchecked power, you must kill Manjong and Manjeon."
"!!!"
Why did that snag so deep?
"We're no dragon seed. Show a chink, and it's the Yi Uimin end for us. Then you'd slaughter endless foes."
My mind went blank white.
When I snapped back, I'd left Dobang somehow—back at the mansion.
Until now, I'd seen Choi U as Father, past-life memories blinding me to what I'd glossed over.
Father had imprisoned brother Choi Hyang. Grandfather Choi Chungheon did the same to Choi Chungsu.
I'd sought power to rewrite history.
Kill Manjong and Manjeon? That easy?
Even if one took the throne, I'd planned shadow oversight. Black style.
If Father handed me power, could I yield to the brothers?
If I pushed one as successor—could I swallow it?
"Probably not."
Why hand the Goryeo I dragged up by the throat to them? Retire to the back room?
Kill them? Or let them idle as wastrels?
What future awaited?
Staring at my hands, they looked stained with blood.
Right. My 21st-century Korean life? Just a past existence.
Now, I was Choi U's daughter. Diverged from the history books, but still clawing for the warrior-regent's seat.
Past-life memories were just that—past. I was me.
I'd viewed the world too rosily. My perch: one slip, total ruin.
"Miss? Miss?"
"Huh?"
"Something happen?"
"What?"
"For a second, your eyes went scary like the Lord's—and you smiled."
"Me?"
Chunsim was sniffling.
"Yes. Like the Lord was about to... Er, never mind."
Couldn't spit it out.
What had those two even done wrong? History brimmed with kin-slaying for thrones, but being it? Different beast.
To lock in succession. To shield the clan. Hands would run red eventually.
Especially in this woman's body, unlike my past life. Easy to dismiss. Martial limits too.
All the more reason: master people.
"Chunsim, you're on my side."
"O-Of course?"
"Yeah. Right you are."
What could one maid do? Time for me to tread the bloody road ahead.
Table the brothers for now. Couldn't slaughter my dear little bros myself, after all.