Goryeo Great Wall
I wonder if I could really live for a few hundred years—how would that even be possible? Hmm. No, before that, I should try making syrup from corn.
As I said before, even if you use corn to make malt syrup, the sweetness tops out at the level of rice-based syrup at best. Yeah. It's still a far cry from modern sweetness. But that's only when using Goryeo's traditional malted barley method on corn. The kind of liquid fructose in modern cola or soda requires enzyme technology that's absolutely impossible in the 13th century.
But don't I have vast future knowledge stored in my head? Even without enzymes, I can forcibly break down corn starch into a highly sweet, clear glucose syrup. The reason this idea popped into my head is... well, look at this corn, right? It's turned out surprisingly edible. Lucky for us, the natives must have brought only the tasty varieties, and the ones we planted have been a huge hit. So, I decided to produce it.
"What is this?"
"It's corn starch. You can make syrup with it too. It can provide sweetness to replace the sugar from Song's temples."
"Does this corn syrup taste that sweet?"
I lightly shook my head at Yi Jang-yong's question.
Goryeo already had advanced ironworking tech. Distill iron in pottery fired to 1200~1300 degrees to get sulfuric acid, dilute it heavily in water. Dissolve corn starch powder in the dilute sulfuric acid water and boil it furiously in a massive cauldron—the acid acts as a catalyst, breaking the starch down into pure glucose. Of course, you can't eat it like that or it'd burn your esophagus. You need a neutralization step to remove the acid. Add lime powder or crushed shells. The sulfuric acid and lime combine into gypsum, neutralizing the acidity, and the gypsum powder sinks to the bottom. That's safe. Filter out the residue, then boil down the clear liquid left behind, and you get a sticky, transparent, high-concentration glucose syrup like honey.
It might fall a bit short of actual sugar, sure. But compared to Goryeo's traditional syrup, it's at least twice as sweet.
"What do you think?"
"This is incredibly sweet."
"How can it be this sweet?"
Yi Jang-yong and the Yodong office bureaucrats were stunned. This would be perfect to distribute to the local lords in Liaodong. We couldn't import luxury sugar willy-nilly, after all. Such a shame.
In the future, climate change and greenhouse methods allow sugarcane cultivation, but to get proper sugar, you'd still have to go to Taiwan eventually. But to head to Taiwan, we'd need a decent pretext, consider the situation there at this time, prepare countermeasures, and only then move. Until then, there's stuff I want to try making myself if possible.
So, how would the price of this glucose syrup compare to traditional malt syrup? Extremely cheap, for starters. Traditional syrup uses malted rice, glutinous rice, or barley—sacrificing human staple food, so it can't help but be expensive. But corn has vastly higher yield per area and grows abundantly in Manchuria. Using this massive corn harvest keeps costs low—no way the price would be high. Production costs drop to a tenth of traditional syrup, and it's way sweeter to boot. Plus, with chemical decomposition, it's done in 1~2 hours.
The leftover corn husks and embryos can be pressed for oil or used as livestock feed, and the gypsum as building material—no waste. That said, we don't have mass production systems yet, so once preparations are done and we scale up, we'll distribute it everywhere. For now, supply it to Yoyang's castle lords.
And it's not just syrup—with these crops, we might even make liquor. Shochu, that is.
"By the way, those workers. I heard there are even Japanese among them."
I was racking my improved brain—thanks to that old man who sent me here—figuring out how to make shochu when Kim Jun suddenly brought it up.
"Yeah."
"Won't they catch diseases or something? Even if they're from the Sho clan, they're probably just rootless samurai wandering the Japanese islands."
Hmm. Fair point—mix all kinds of people together, and trouble might brew. Especially with Goryeo folk, Khitans, Jurchens, Japanese, Han Chinese all crammed in one place. Friction's inevitable. Even if it's clean by this era's standards, couldn't some plague spread? That reminded me of something.
We're doing 8-hour shifts, but won't the sweat stink be brutal on those wall laborers? Goryeo people bathe well, but maybe we should make it even easier for them.
Suddenly, it hit me. Yeah—bathhouses.
I get hot water from Chunsim almost daily and bathe. Washing my hair with soap, scrubbing my body too—twice a day at least, once minimum. Goryeo folk were pretty clean to begin with. They were open-minded; men and women bathed naked together in rivers without a second thought. No wonder Song envoy Seok Gung wrote in his account of Goryeo's capital: 'Ancient histories record Goryeo customs as all clean, and it's still true. They always mock Chinese for being filthy.'
The Book of Wei says, 'Regardless of high or low birth, they love cleanliness.' From ancient Goguryeo to now, Goryeo people loved bathing. But from Joseon onward, Confucianism killed that. Strict gender separation made full-body baths showing nudity to others a breach of propriety. They settled for partial washes—hands, feet, face. Partly due to lacking facilities, but social views turned negative too. All Confucianism's fault.
Oh, Confucianism—what a horror. If some Joseon-like country time-traveled next door, I'd send an army to conquer it on the spot. Living that dirty, suffering from boils and all. No Joseon in my era, so I'll keep Goryeo's hygiene going for a thousand years.
"No matter how much they like bathing, hauling water is hard labor."
Even Rome had public bathhouses, right? We could build some. With cement, cement tubs would be best. Stone takes too long. Need a massive hot bath for hundreds at once. Ondol floors in changing rooms and lounges for toasty warmth. Coal-fired boilers to heat water. Plenty of soap already. Issue is pumping water—use the Taejah River. Adapt the steel mill's bellows into reciprocating pumps to draw and lift it. Piping's already there from sewers—connect with clay and cast iron pipes to the baths.
Then faucets. They've existed since Roman times, no big deal. To prevent rust, make brass. No rubber gaskets, but thick cowhide works. Zinc's available on the peninsula; mix with copper. To make brass in this era, roast copper and zinc—carbon infiltration method, used even in Roman times. Put copper scraps, zinc powder, and charcoal in a sealed crucible, fire it up—brass. Development in 3 months tops. Put it in Yoyang Castle. Spare pipes aplenty; just make faucets. March now—start immediately, not bad. Completion near summer opening.
Sounds good.
"Let's build bathhouses with the spare laborers."
"Bathhouses?"
"Don't we need more public bathing spots for a people who love cleanliness?"
While at it, build a simple one near my house. Hauling water every time's a hassle. River mixed bathing? Hmm. Raised open-minded in Goryeo, I don't mind, but still—a bathhouse is better.
I immediately mobilized spare workers for bathhouse construction. Spare pipes too. Max 3-month build.
"This is massive construction."
Massive? It's all thanks to cement—that's the real wonder.
"Yeah. But we'll separate by gender, and add a mixed bath too. Not bad, right?"
Men's, women's, mixed. How's that?
"Bathhouses, huh." Kim Jun stared at the site thoughtfully.
"What, wanna try mixed bathing?"
"As if."
Come to think of it, Kim Jun's got some presence now. Feels like looking at an eunuch character. Grew up ogling ladies, huh. Might not even steal Father's concubine. Pitiful—he'd be too dumb to eat it if handed to him.
"Never knew lime was this versatile."
"Yeah. That's why it's great."
A thing only usable here in Goryeo? How perfect. Living in such an advanced city—what a treat. With Goryeo-style bathhouses, could rival Song's capital? Nah, Song probably doesn't have giant baths like mine. That's how life goes.
Around this time, Song was on the verge of madness. Or rather, its people.
Not constant plundering, but Jin sent small bands like bandits to block merchants' goods.
"Jin plundered us again! What the hell are our garrison troops doing?"
"Hunkered in castles, responding with those guns or whatever—nothing else?"
"Can't take it anymore. Might as well revolt."
Problem: Uprisings big and small were swiftly crushed. Song wasn't so weak it'd lose to rebels; situation wasn't that dire. Armies get thrashed by foreigners but smash their own citizens—that's the organization for you. With the emperor's authority at its peak now, even plundered victims got buried.
"Let's head to sea. Heard Goryeo's filthy rich lately."
"Yeah, selling tons of ginseng. Raid one ship, our lives set."
When a country's a mess, bandits inevitably rise. Song wasn't there yet, but vast lands constantly raided, court failing—natural progression. But as said, uprisings got quashed fast. Surrender to Jin? No way to that barbarian state. Arming themselves had limits against Jin.
So, sea it was. Like Silla's end with Silla Pirates sweeping Asia, or Japan's wako during Kamakura fall and Nanbokucho chaos. Border folk fed up with Jin raids turned pirates. Targets: Goryeo merchant ships.
"Crazy pirates! Pirates!"
"Kahaha! Hand over everything!"
"Give up the goods quick, and we'll spare your lives!"
Unlike keel ships for expeditions or Daesikguo trade, Goryeo used regular merchants for Song—easy prey for Song pirates.
As bathhouses neared completion, trouble brewed in Asia.
"Song pirates are on the rise lately."
Song pirates? Ah, makes sense.
"Our merchants getting hit helpless?"
"Damage isn't huge. Merchants arm private guards with matchlocks to fight back."
Right—keel ship builds reformed the fleet, so we allowed merchant self-arming. State supplies matchlocks and cannons for trade protection. Need proper cannons soon.
"But if we let it slide, pirates multiply, our losses grow?"
"Yes. Solve it before then."
"Hmm. Send some keel ships."
Keel ships mount cannons now. Coastal defense fleet in mind, but this profits more immediately. Recruit or exterminate Song pirates to secure sea lanes.
"What if they raid a keel ship?"
Raid a keel ship? Looks tough to me.