On September 22, Jin was guiding Sion (in her Sion D form) and her party—an inspection delegation from the Nord Federation—to Toka Village.
This time, they headed for the village's original airfield rather than the one Jin had newly constructed. Measuring only about one hundred meters square, the old strip would be far too cramped once the massive crowds arrived for the Marikka Cup.
"When the time comes, we'll have them use the airfield a bit further west."
"Ah, that one....It's quite spacious. That will do nicely."
The Doppel had exceptional eyesight, allowing Sion D to immediately spot and identify the western airfield.
The Hurricane, carrying Jin and the others, gently touched down on the tarmac.
Having been notified in advance, Magic Technology Minister Cowen Lacca Kido and his subordinates were on-site to receive the group, accompanied by Village Chief Yuzo Mayaka.
"Ah, Sion-sama, Jin-dono, welcome."
"You seem in good spirits, Cowen-dono."
"Indeed, thanks to you."
"Chief, thank you for coming out to greet us."
"Y-Yes! It is an absolute honor to welcome you, S-Sion-sama!"
"Jin-dono, a pleasure to have you here....I've heard about the progress on the mine's development."
"Is that so? Thank you for having us today."
"This is Istash of the All-Creation clan. He is an architectural engineer."
"Oh, we would love to learn whatever you can teach us."
"The pleasure is mine."
After concluding their formal greetings, the party boarded the prepared Golem automobiles to travel.
It was scheduled as a day trip... or rather, under the official premise that Jin would be personally taking care of Sion's party. The public reasoning was to avoid placing any undue burden on Toka Village while it was still under development.
"That is the hotel currently under construction."
"It looks magnificent."
Istash of the All-Creation clan, who had accompanied Sion D, spoke up. He was a sturdy man who appeared to be around forty years old.
Naturally, he had already been briefed by Jin and Sion. He was one of the central figures for today's operation.
"From what I can see, the structure is made of granite, correct?"
"Indeed it is."
Cowen also possessed a solid working knowledge of stone masonry.
"Granite is rather brittle. Have you taken any measures to address that?"
"Well, about that... We are heading there now, so let us inspect it on-site."
And with that, the plan was set.
Viscount Gillet Feza Lutria, head of the Third Technology Department of the Ministry of Magi Technology, who was serving as the site supervisor and local project lead, stepped forward to meet the arriving automobiles.
"Welcome, everyone."
Stepping down from the carriage, Magic Technology Minister Cowen Lacca Kido immediately turned to his subordinate.
"Gillet, have you run into any difficulties or issues?"
With Magi Craft Meister Jin and architectural engineer Istash of the All-Creation clan both present, this was the ideal opportunity to consult them.
"Yes, Your Excellency....To be frank, I have been agonizing over how to accurately gauge the strength of the stonework."
Viscount Gillet Feza Lutria was an honest man who prioritized practical results over his personal pride. In the end, this candor would protect the honor of the Klein Kingdom.
"The exterior was modeled after the Jade Villa on Kunlun Island, wasn't it?" Jin asked.
"Yes, precisely. It is such an exceptionally superb design that architects all across the world look to it for inspiration."
Hearing this, Jin thought to himself, So that's how it is.
However, Istash of the All-Creation clan offered a word of caution.
"Is it not dangerous if you fail to account for the material properties? As the name suggests, the Jade Villa is constructed from jade, which is an exceptionally tough stone. Granite, on the other hand..."
To this, Viscount Gillet Feza Lutria replied with complete honesty.
"I am well aware. That is why we incorporated structural reinforcement throughout to compensate for its weaknesses, but... I still lack confidence in our approach."
"I see. So you understand that granite is brittle. In that case, would you allow us to inspect the interior?"
"Gladly....Please, we would be deeply grateful for your guidance."
With that, the party stepped inside the unfinished hotel.
"I see..."
After examining the surroundings, Istash delivered his assessment.
"The reinforcement is insufficient. In the worst-case scenario, the roof and floors could collapse."
"What?!"
"No, it is safe for the moment. The load-bearing strength is adequate for now. However... ten years down the line, I cannot guarantee its safety."
Granite was hard, yet brittle. Istash explained that it should never be used in areas subjected to bending stresses.
"If you were using steel frameworks as the primary structural members and simply facing them with granite, that would be entirely acceptable."
"I see, that makes sense."
"A weakness to bending translates to a weakness against tensile stress. Naturally, granite possesses great compressive strength, so it can easily bear the typical loads applied under ordinary conditions."
Istash concluded his explanation by noting that repeated impacts and shocks would gradually degrade its integrity over time.
"I understand. That is truly educational."
Istash then offered an additional point.
"Of course, it is entirely possible to construct a building like this using only granite—provided the design accounts for the structural mechanics."
In short, he explained that they needed to minimize any points where the structural elements would experience tension.
"For instance, by using arch structures in the sections that support beams and floors."
"I see...!"
"Indeed, this is a tremendous learning experience."
Listening from the side, Jin was thoroughly impressed and found the lecture quite insightful.
Jin himself was not particularly knowledgeable about architecture. However, he understood the fundamentals of structural mechanics, which Laojun had used as a foundation to conduct extensive experiments and verifications leading up to the present day.
Such knowledge had also been disseminated among the general public in the Nord Federation, leaving them far more advanced in this field than the Lauren Continent, where technological heritage had been severed by the Magic Federation.
Jin believed that the arch was one of the fundamental archetypes of masonry construction.
The Roman aqueducts he had seen in photographs were built on that exact principle.
Openings in brick structures were likewise almost always arched.
"Arch structures are inherently strong against downward loads, after all."
"That is certainly true."
Watching the Klein Kingdom's engineers hang on Istash's every word, Jin felt a twinge of regret that even the most basic tenets of structural mechanics were now only partially remembered in these lands.
"I would recommend applying Toughening to reinforce the structure....Jin-san, would you mind lending a hand?"
"Of course. After all, safety isn't something money can buy."
Everything was proceeding precisely according to script.
It was a scenario crafted by Laojun to create a natural justification for casting Toughening without raising suspicion.
"...Toughening."
"Toughening..."
Jin and Istash went to work applying the magic.
Because of the effortless manner in which they performed the casting, the onlookers failed to notice the reality of what was happening: with Jin stacking his own magic directly over Istash's, the effect was fortified to endure for several centuries.
Jin had no desire to see an accident ruin such an anticipated event, so he was more than willing to offer his assistance.
So long as it was done naturally, of course.
As a result, this hotel would eventually go down in history as one of the Klein Kingdom's most celebrated architectural masterpieces—though that is a story for another time.
"Mm... That has made it a truly robust structure."
Having inspected the entire building, Istash of the All-Creation clan nodded in satisfaction.
"Thank you very much."
Cowen and Gillet bowed deeply in gratitude.
"Had an accident occurred, our kingdom's credibility would have been utterly ruined."
"Please, come to the Nord Federation someday to study architecture."
Istash of the All-Creation clan smiled warmly. "You will be more than welcome."
Inspired by this encounter, Viscount Gillet Feza Lutria would eventually secure royal permission to study abroad in the Nord Federation for two years—though that, too, is a story for another time.