With the engagement ceremony concluded without a hitch, Jin returned to his mansion in Loizart. That night, he spent his time relaxing for the first time in quite a while.
As expected, visiting his fiancée's family home had been a nerve-wracking experience.
The following day, the 27th.
Jin set out for Hourai Island alongside Elsa to get the automobile project underway at last.
＊ ＊ ＊
Inside his workshop at the Hourai Island laboratory, Jin began by sketching out a rough outline of his plan.
However, he immediately hit a snag.
"Hmm, how should I handle this..."
"Jin-nii, what's wrong?"
Since it was rare to see Jin looking so troubled, Elsa called out to him, her voice tinged with concern.
"Oh, Elsa. I was just thinking about the automobile. Do you mind listening for a bit?"
"Mm."
Sometimes, when one is stuck, talking through the problem with someone else can reveal a new path forward. Elsa sat down across from Jin to hear him out.
"To start with the premise—you know the Konron 2, right?"
"Yes."
"Its appearance and its internal components don't exactly match."
Elsa nodded in agreement.
"Then there's the Shark. That was another vessel I built while imposing certain restrictions on myself."
"Mm-hmm."
"...So, regarding the automobile, I was thinking of applying similar restrictions. I want to make something where the outward appearance and the inner workings feel a bit mismatched."
"I agree. I think that's a good idea. But was that what you were worrying about?"
As far as Elsa could tell, that didn't seem like much of a problem.
"No, that was just the preamble. When I made the Konron 2, I distributed hot air balloons. I was wondering if I should do something similar this time."
"Are you going to give away automobiles?"
Jin shook his head.
"That's the dilemma. For now, I'm torn between two choices: distributing the Golem Engine itself, or a simplified automobile..."
Just then, Reiko arrived carrying glasses of citran juice.
"Father, it is bad for your health to push yourself too hard. Please, take a moment to rest."
"Ah, thank you, Reiko."
Since there were two servings, Elsa joined him.
"...Delicious. So, can I give you my opinion?"
"Of course."
"I think providing the engine alone would be enough."
Golems were already an established technology, Elsa pointed out. In the Kingdom of Elias, they had already seen Arrow create rotational motion by having her pump pedals. Elsa summarized that, given the circumstances, it wouldn't be strange for someone to eventually develop a Golem Engine.
"I see. That's a valid point..." Jin nodded, convinced.
After Elsa finished her citran juice, she spoke up as a memory surfaced.
"By the way, Jin-nii, wasn't your carriage designed to run even without golem horses?"
"Eh? Oh... right, it was."
Elsa gave him a playful, mock glare.
"Your bad habit, Jin-nii, is making things and then just leaving them as they are."
"Hmm... I have far too many instances of that to even try to argue..." Jin finished his citran juice and offered a wry smile. "But you're right. A carriage... yeah, for the design, I think a classic car look would be best."
It seemed Jin had finally learned that creating something with a design too far removed from the standards of this world actually made it difficult for people to use.
"Well, it's not like it needs to fly through the sky."
Jin recalled a Western movie with a flying car in the Orphanage Director's video collection, but he intended to make this one a proper land vehicle—or so he thought at that point.
The day felt short due to the time difference. Jin spent the remainder of his hours fleshing out his concepts.
The project began in earnest on the 28th.
"First, we'll build the engine."
"Mm."
"Yes, please leave the assisting to us!"
"What shall I prepare?"
Jin set to work on the crafting alongside Elsa, Reiko, and Edgar.
"Let's start with the units we'll send as samples to each country. The material will be iron. To be precise, carbon steel."
Jin had Reiko prepare a block of iron weighing about two hundred kilograms. To that, he added carbon separated from atmospheric carbon dioxide to create carbon steel with a carbon content of 0.5 percent.
"The configuration will be two-cylinder... no, let's call it a Dual Golem Engine."
Structurally, since the image was of legs pushing pedals, 'Dual' would be the basic form. The hip joints would be located where the cylinder head of a gasoline engine would be, the pistons would act as the legs, and the crankshaft would serve as the pedals.
"As for the size... well, for practical use, let's make it about fifty centimeters tall."
At this size, it could produce enough power to move a carriage without needing a reduction gear.
"For the magical muscle, we'll use standard... no, that might not be right. I believe we have some Death Sea Serpent leather, so let's use that."
This material came from the magical beast they had encountered previously in Port Rock Town, at the southern tip of the Kingdom of Elias. They occasionally appeared around Hourai Island as well to prey on the local fish. Any that entered Tatsumi Bay were exterminated to prevent them from damaging the aquaculture pens.
While explaining the process, Jin built the first unit himself.
"I see. This looks interesting."
"The structure is simple enough. It's quite heavy, though, so make sure you have Edgar hold it firmly for you, okay?"
"Mm."
For the bearings, he used gunmetal—an alloy of copper with tin and a small amount of zinc. Finally, he set a control core at the very top of the cylinder head—the part where a spark plug would be installed on a gasoline engine—and connected it with control wires.
In this manner, while providing commentary, the Dual Golem Engine was completed in about an hour.
"Now, you try making one."
"I'll try."
While Jin provided subtle guidance on the points Elsa found confusing or difficult, she finished her Golem Engine in about two hours.
"It's a fine piece of work."
"Thank you. It's only because of you, Jin-nii."
Elsa was being humble, but Jin hadn't actually lent a hand; he had limited himself to only pointing things out until the very end.
"There's a little less than an hour until lunch. I can manage one more."
"Mm."
This time, without Jin watching over her, Elsa finished an engine in half the time—exactly one hour. In the same span of time, Jin had completed three engines.
"When I look at you, Jin-nii, I feel like I'll never have any confidence in myself..."
Such was the quiet outpouring of Elsa's true feelings.
The six completed Golem Engines were scheduled to be sent to the Klein Kingdom, the Franz Kingdom, the Celuroa Kingdom, the Kingdom of Egerea, the Kingdom of Elias, and the Shouro Empire.
"My Lord, it is worth reconsidering whether you should provide these for free."
Loll, the blue-haired automata who had come to clean the workshop, offered a word of caution.
"I suspect that these are incredibly rare Magi Machines—the likes of which are likely found nowhere else in the world. I believe it would be wise to request some form of compensation."
"Jin-nii, I agree with her."
"Hmm, I see."
Jin often struggled to accurately estimate the value of his own skills. He felt grateful to have such things pointed out to him.
"Well then, what should we do...?"
"You should avoid taking payment in money."
"I know that."
Even without Elsa's reminder, Jin had very few opportunities to spend money. Since Hourai Island was self-sufficient, he could make almost anything he wanted. Furthermore, if he did nothing but hoard wealth, it could lead to economic stagnation in the outside world.
"Materials, then?"
"Mm. You can never have enough of those. Their value stays the same even as they age."
Elsa added that in the unlikely event of a future shortage, they could always release their stockpiles back into the world.
"Materials that can't be harvested on Hourai Island would be good, too."
Amber and limestone were not naturally produced on Hourai Island, though limestone had been discovered on the seabed. Additionally, as mentioned before, their copper production was relatively low. However, since the applications for copper and copper alloys like brass, cupronickel, and bronze weren't that numerous for them, it wasn't a major issue.
"My Lord, while amber is fine as a gemstone, it isn't used much in magi-craft. In that case, copper would indeed be more practical."
Even Laojun joined the discussion.
"Hmm, that's true."
"...What about leasing land and doing something there?" Elsa proposed, an idea clearly forming in her mind.
"Doing what?"
"Mm. For example, laying down a railroad. Or building a school."
"Ah, that's another interesting direction..."
Jin remembered that horse-drawn railways were also a part of history. His dreams were expanding, but he knew they couldn't all be realized immediately. The future was still shrouded in mist.