Waking the next morning, Jin finished his breakfast and got straight to work on making gears.
His first step was to create a linear gear to serve as a reference. He prepared a strip of adamantite and began crafting the teeth. He didn't worry about the module—the standardized gear tooth size—since he was working solo. He would simply establish his own standard.
"This should be about right."
Since these were for an automobile, they needed to be strong. However, considering he was using adamantite, he felt confident that even smaller teeth would hold up. It was always easier to scale up later, so he decided to start with the smallest size he could manage.
He produced two hundred copies of his first prototype tooth. It was a simple task. By lining them up facing each other, the spacing between the teeth became naturally uniform.
"All right, now if I use 'Fusion' to join one side to the strip... Done!"
He had completed a rack—a linear set of gear teeth.
"Now I just use this to make another rack with the desired number of teeth... Yeah, that's a success. Next, I'll use 'Forming' to bend this into a circle. With that, the outer rim is finished."
At this stage, he had the outer ring of teeth for a gear with a specific count. It was, essentially, a donut with teeth.
"Now I just use 'Fusion' to fill the center with material, and... I did it!"
Before Jin's eyes sat a perfect spur gear.
He quickly made a second gear with a different tooth count and tried meshing them together. They fit perfectly. The movement was so smooth he nearly felt like dancing.
Now that he could produce spur gears, he could manage to make bevel gears as well—though only between gears with the same number of teeth for the time being. Still, the ability to change the direction of rotation by ninety degrees was an enticing prospect. The variety of machinery Jin could now build expanded instantly.
"All right, let's build a car!"
He crafted the chassis out of light silver. Getting a bit carried away, he built a four-linked engine. He even made proper rubber tires, spending the entire afternoon finishing the automobile.
"Yes, this is quite comfortable."
Since the vehicle lacked a transmission, he operated it with only an accelerator and a brake. It wasn't exactly an automatic; rather, the Golem Engine's power delivery was so consistent that this simple setup was perfectly viable.
Jin spent a while driving around the flat ground in front of the laboratory. He eventually stepped out with a look of immense satisfaction, only for Reiko to pose a question.
"But Father, don't you think a Golem horse would have more utility?"
"Eh?"
Jin didn't understand her question at first, but the meaning soon dawned on him.
For the sky, he had the Magi Jet Engine. For the sea, he had the Magi-Water Jet. Naturally, he had assumed the land required a Golem Engine. However, the roads in this world were not only unpaved, they were barely even leveled. In such a world, how much use would a car actually see?
"Hmm, I suppose it might just be for my own satisfaction. Oh well, I can at least use it as my personal transport on the island."
With that decided, he issued his orders.
"Reiko, have Topaz lead the construction of a road network across the island. You don't need to pave the surface, but apply 'Solid' to the dirt. That will prevent weeds from growing and ensure the ground can handle heavy loads."
"Understood. May I prioritize construction for the major facilities, such as Tatsumi Bay, the fields, and the airport?"
"Yeah, that sounds like a plan."
Since he had already built an airport for the planes, road maintenance was an urgent task. He had installed large Warp Gates in various locations, but a proper road network was still a necessity.
"Man, I'm starving."
By the time they finished discussing the plans, it was pitch black outside.
"Father, I prepared tonight's dinner."
"Oh, did you, Reiko? I'm looking forward to it."
Soleil and Luna were busy mass-producing aircraft and ships, so Reiko had taken over the cooking duties for Jin.
"Is this pure white bread?"
"Yes."
Reiko had baked the bread from flour she made by hand-peeling every single grain of wheat before grinding it.
"Yeah, this is delicious," Jin said, eating the bread and washing it down with a vegetable and fish soup. As he suspected, bread without any bran mixed in was superior.
"I feel terrible that we haven't found any rice yet."
"No, I understand. I won't ask for the impossible. I'll just have to look for it in the western nations next time I travel."
He hadn't found rice in the port town of Port Rock either, but Jin held out hope that the countries to the west might offer different, unusual crops.
On the seventh day since his return to Hourai Island, Jin’s morning began with a new ambition.
"Might as well make a turbine, too."
The principle was simple. He would place an impeller inside a sealed container and use wind magic to spin the blades. If he circulated the wind properly, there would be no need to take in air from the outside, and the air wouldn't leak out. It was remarkably easy to complete.
"Oh, the RPM is definitely high."
In essence, it was a magically driven windmill. The rotation speed was high, though the torque was inferior to that of the Golem Engine.
"Well, it'll probably come in handy for something."
He was simply enjoying the act of creation.
Standing by his side, Reiko also felt a sense of purpose. She meticulously organized and stored the data on every work Jin completed, ensuring she could produce replicas at any time. She acted as Jin's assistant memory storage.
"Father, what about our discussion regarding weapons?" she asked, acting as his secretary to remind him of his neglected tasks.
"Ah, right, I did say that. We need them for our defense."
Jin fell into thought.
"A Water Jet, a Laser, or maybe Induction..."
After weighing his options, he decided to make the Laser standard equipment. He chose it because it was easy to make non-lethal by adjusting the intensity, defense methods against it were limited, and it was easy to aim but difficult to evade.
"All right, let's get to work."
He had Reiko fetch the materials and began fabrication immediately. The structure was simple. It was shaped like a slender wand, with a magi-formula inscribed inside.
"I'll also need some authentication."
"Father, what is authentication?" Reiko asked, hearing an unfamiliar term.
"Ah, well, for example, if someone were to steal it, I want to make sure they can't use it."
He rigged it so the device wouldn't operate without Jin's specific magical waveform. He dubbed this feature the "Certificate." Since the golems Jin made—and Reiko herself—all inherited Jin's magical waveform, they would be able to use the weapons without any issues.
"That should do it."
The prototype was finished. It looked like a simple, unassuming cylinder. He hadn't bothered giving it the shape of a handgun.
"Shall we test it?"
He stepped outside the laboratory and aimed at a rock pile at the edge of the plaza. He fired the Laser. A beam as thin as a needle shot out, piercing through the rock in a matter of seconds.
"All right, it's a success."
He adjusted the settings slightly and fired again. This time, the beam was more diffuse. The range was shorter, but it instantly vaporized the rock it struck.
"This is dangerous. I can't let this be used except in emergencies."
With that in mind, he decided to design a second weapon with lower output.
"Paralysis... I see, a stun gun!"
He recalled the Paralyzing Staff Beena had been carrying when they first met in Blue Land. He knew such magic tools existed.
"All right, I'll make something several levels above that."
Jin was fired up, but Reiko intervened.
"Father, it is almost noon. Please eat lunch before you continue."
Jin obeyed and headed for the Mansion.
"Did Soleil make lunch today?"
The menu was toast, citran marmalade, salad, and a fried egg. It felt more like breakfast, but Jin ate heartily regardless.
"Thanks for the food."
As soon as he finished, he headed back to the laboratory.
"As usual, Father loses sight of everything else once he starts making things," Reiko murmured. She followed close behind to provide support.
The stun gun was completed quickly. Since he had analyzed a Paralyzing Staff before, he was able to compensate for its flaws and increase its efficiency. He created two versions: a wand about thirty centimeters long for his personal use, and a baton-shaped version for general security. The wand was made of light silver, while the baton was a Composite of adamantite and mithril.
"In that case, let's establish an Army."
Jin proceeded to create twenty golems, naming them Land 1 through 20. With that, Hourai Island finally possessed its own Army, Navy, and Air Force.