Rice (2)
"Young Master. Everyone has assembled."
"Very well. Shall we begin?"
The master craftsmen of the engineer battalion, having received my orders through Old Max, had gathered on the grand duchy's open grounds with every material I had requested.
Most of their company had been sent out to other regions for hanok terraforming projects, so the engineers themselves were few—but the soldiers drafted to haul the loads made up for it in numbers.
I stepped in front of them and raised my voice.
"Greetings, everyone. I am Logwell Wintershield, the Second Young Master—though I expect you already know my face. Even if you don't, you must at least remember the gukbap you ate not long ago."
"Of course we do!!!"
"We ate like kings thanks to you, Young Master!!"
"I knew who you were already!!!"
The response was excellent.
Well, even dogs that can't tell their own master at home will still recognize whoever feeds them. Not that I was calling these men house pets—but it was solid proof of just how thoroughly a free meal carves itself into memory.
"Good. The ingredient that made that meal of yours is rice. Without rice, there is no rice bowl—so you could call it the foundation of everything. And from this day forward, we are going to make the rice of the construction trade."
I declared it with full ambition before the assembled ranks.
The ordinary soldiers, who didn't fully understand what I meant but decided it sounded good anyway, cheered. The engineers who actually knew their craft, however, looked worried.
"Rice?"
"With this?"
"Isn't that far too soft?"
Fair enough.
What I had ordered the regular soldiers to gather was foundational rock for building. But by the standards they knew, those stones were far too soft to use as construction material.
Still, the fact that they collected it just because I said so goes to show how much weight the title of Second Young Master carries.
Words alone would never kill their doubt. A hundred hearings were never worth a single sighting.
I lifted one of the stones they had brought and asked,
"All right, gentlemen. Do you know what this is?"
"Limestone, isn't it?"
"Correct. And as you all know full well… limestone is rather soft."
Crack—
I raised the limestone high and flung it down onto the ground in front of them.
Even the sound of it breaking was pathetic, and the engineers' already skeptical looks only darkened further.
But this was the correct step. More precisely, this whole process had to be gone through.
"Which is why we can't use it as is. First, all of this has to be smashed. So your first job is to pulverize every last piece of this limestone into powder."
"Uh… right now?"
"Yes. Right now."
Still tilting their heads, the engineers took up their hammers. True to their hardy northern stock, they reduced the limestone to powder in no time at all.
"We're finished, Young Master."
"Well done. Now pour it all into the prepared barrels."
"Huh? Young Master, there's already sand and water in—"
"I know. Pour it in and stir thoroughly with the large paddles we've set out. Ah—and measure it into the prepared containers first so the proportions are correct."
That's right.
What I was making was none other than cement.
The name makes it sound like a modern invention, but cement actually appeared in human history five thousand years ago.
What I was attempting now was not modern cement but a thoroughly primitive version of it. You mix powdered limestone with sand and water—and for the record, the limestone powder itself is the cement. Mix sand and water into it and what you get is called mortar.
Skip the sand and mix only water, and you get a cement paste.
Even cement paste alone would count as a revolutionary invention in this era.
From what I had learned, most castles of this age were either stone fortresses or brick fortresses—walls of fired brick. The grand castle of the duchy itself fell into the brick category, though more accurately it was a mixed construction of stone and earth used like brick rather than pure masonry.
If even a grand duchy settled for mixed construction, the rest of the castles were probably in the same boat. At first I wondered what kind of nerve let people build fortresses like that in an isekai where war was genuinely common.
But then—
I looked into it, and of course it all came back to magic.
In the magicless modern world, the method of fortification and the materials themselves decided a castle's entire defensive power. In this world, a wall was nothing more than a blank canvas—the real defense came from the picture painted on top of it in magic.
Hardness reinforcement, strength reinforcement, durability reinforcement—once every enchantment under the sun was slapped on, even a plain brick wall could hold its own against a bunker. So everyone treated the physical structure as little more than base decoration.
Everything was the product of meaningful evolution, I supposed. And at the same time, another thought struck me.
Wait. Then the people who don't benefit from magic are literally stacking rocks and entering the prayer meta, aren't they?
Shockingly, that was exactly the case. Plenty of northern villages didn't even have earthen walls or proper wooden forts—just wooden palisades.
So I decided to start here.
Even if you only smear cement paste between pure brick courses, the adhesive strength skyrockets and the defensive power rises to a startling degree. But is there any reason to stop there?
As I said, mix cement paste—cement plus water—with sand at a one-to-one-to-one ratio and you get mortar. Mortar doesn't just glue things together the way cement paste does; it fills gaps and builds a consistent thickness across walls and floors.
And then—
"Once it reaches a proper paste consistency, add the gravel from the sacks on the side."
The moment you fold gravel into the mix, something far more familiar is born: concrete.
The legendary gonguri, as we called it.
Strictly speaking, gonguri is just the Japanese-derived military nickname for concrete—but in the army it was the umbrella term for every act of spreading cement. Working concrete was gonguri. Spreading plain cement was also gonguri.
How many broken flowerbed corners did I patch with this stuff?
One of the things I did most often while trailing after a certain three-star Octopus General was exactly this. Thinking back on the days of standing around with a shovel, slapping on cement, still brings tears to my eyes. Hard to say whether I was an officer or a private at that point.
Still—looks like that experience is finally paying off.
At first I truly knew nothing and just flailed. But watching the senior NCOs and the occasional civilian contractors out of the corner of my eye, I eventually reached a respectable level of competence myself.
And while I was lost in old memories, the concrete—cement, sand, water, and gravel all mixed—came together.
"Now pour this into the prepared wooden molds and let it set."
Properly curing concrete meant mixing, pouring, watching the hydration reaction, and waiting for strength development. But there was no way I could dump all of that on them at once.
I kept it simple: it would start to harden in one or two hours, but it would take a full day before a person could safely stand on it.
Removing the forms takes three days. Reaching about seventy percent of full strength takes seven. True full strength takes roughly twenty-eight—but that was far too long to wait. In winter it can stretch to three months, and the North is winter year-round, so waiting that long was out of the question.
What I needed was an immediate demonstration of performance.
After gathering a few more necessary items, I ordered everyone to disperse and reassemble in one week.
And when that promised week had passed—
"…You're telling me this brick was made from that soft, crumbly limestone?"
"Oi, it's not a brick—His Lordship called it concrete!"
"What kind of strength is this…!"
They were witnessing a new world.
"Compare it to a regular brick."
For the most extreme demonstration possible, I had them pit it against bricks they had fired and stored in the warehouse. Ordinary brick against concrete brick. Concrete brick against ordinary brick.
The result was a total victory for concrete. Even across ten straight matches, every ordinary brick lost and every concrete brick survived.
"Can you feel the difference in power?"
"Y-yes, I can…!"
"And what do you think of my concrete bricks?"
"They're huge… and beautiful…!"
The regular soldiers reacted with little more than oh, the Young Master invented another weird thing. The engineers who had spent their lives in construction could not close their mouths.
A concrete brick ten times stronger than a regular one did not simply mean ten times the defensive power. Ordinary bricks already multiplied their pure defense when stacked together—so how much could a wall of these concrete bricks raise that number?
The moment that thought landed, the engineers' eyes were drawn, as if spellbound, to the sacks of limestone and cement.
And the most attractive point of all—
"It only took a week?"
"No constant fussing over drying and firing, either…"
"To bake bricks you need the kiln running forever, but this…"
—was how overwhelmingly simple and short the production process was. Engineers who had suffered through firing bricks stared at the concrete blocks with glazed eyes.
"And we won't simply stack them. If you spread cement paste between the courses like this, the adhesive strength rises—and so does the overall defense."
I showed them a short section of wall I had already pointed up with a trowel while waiting. The murmurs rippled outward at once. Even at a glance, the finished work looked anything but ordinary.
Then someone spotted another pile of materials stacked off to the side.
"Young Master—what is all that, then?"
Ah. They'd seen it.
I grinned and pointed to the stock I had spent the week collecting through Kim Cheolsu Distribution.
"The concrete I've shown you has every virtue—except one flaw. Its tensile strength. Its ability to resist a pulling force is weak."
Compared to the wooden palisades they had been building until now, it barely counted as a flaw—but if we were going to do this, we might as well do it properly.
In the modern world, this problem was solved by mixing in rebar—reinforced concrete.
It was a composite method of combining different materials, and under ordinary rules it should never have worked. No matter how strong each material is, different coefficients of thermal expansion mean that when temperature shifts, the volumes change at different rates and create gaps or cracks inside the structure. But steel and concrete expand at nearly the same rate, so a simple adjustment of the mix ratio solves it.
There was a reason rebar-and-concrete was called a gift from the gods of engineering.
The problem is, this world has no rebar.
Metallurgy here seemed fairly advanced compared to other fields—but no one had ever needed rebar, so the concept itself had never developed. And given that every scrap of iron produced in the North was forged into weapons and shipped northward, an alternative was essential.
So what I had prepared was this:
"This is bamboo—a plant that usually grows in the hot, humid south. If you set it into the concrete as it hardens, you won't even need to cast separate bricks. You can pour entire fortress walls!"
Bamboo-reinforced concrete.
It sounded absurd, but it was a technique Imperial Japan had actually tested during the Second World War.
In military science class I just thought, typical Imperial Army nonsense—but it turned out to be a real, workable method.
Of course, it fell far short of true reinforced concrete. On columns or beam bridges under serious bending stress, the maximum viable span was only about four meters.
But as always, our point of comparison was the wooden palisades they had been using before.
If we could roll this out across every northern holding and raise concrete walls—
"I promise you this. A future in which our North no longer suffers under monster raids!"
Monsters?
Without concrete walls, you were the ordinary ones.