The next day, Jin was on Hourai Island.
"I’ve decided. I'll send Smith units 401 through 410."
"Understood, My Lord. I will monitor their progress and consider sending reinforcements if necessary."
"That sounds good. Gon and Gen have been managing on their own, but we should have them return to Kaina Village as soon as the Smith units arrive."
That settled the matter of the road hardening for the time being.
"Now then, it’s time to focus on what’s most urgent."
"You mean the Space Isolation Barrier?"
"Exactly. Ever since I realized that a multi-layered structure for the magic circles was the key, I’ve been sketching out several concepts."
Jin began explaining his ideas to Laojun.
"First, since this is going to require a massive amount of free ether, the first layer has to be an ether converter."
"An logical first step."
"The second layer will contain the magi-sequence that defines the barrier’s effective range and strength."
"Understood."
"The third layer is..."
Jin continued to walk through his conceptual design.
"In the ninth layer, we use the gathered free ether to generate a teleportation space. This is an application of a teleportation magic circle."
"We have already mastered the practical use of that technology."
"The tenth layer will be designed to invert that teleportation space."
"That would be the necessary conclusion to achieve the desired effect."
"The resulting barrier should, in theory, completely sever space."
Essentially, it was like placing two Warp Gates face-to-face without their physical housings, separated by a micro-class interval.
In theory, the space between Warp Gates is connected by a subspace. Within that subspace, physical phenomena from the outside world become almost entirely meaningless. This meant that any physical phenomena occurring on the other side of the barrier would not be transmitted through to this side.
The only exception was the movement of matter itself. However, because the gates would be installed at such a micro-class interval, it should appear as if nothing had changed to the naked eye.
That said, Jin speculated that because any intrinsic velocity an object possessed would be reduced to zero upon entry, it would appear to come to an instantaneous stand still.
"Do you believe this could serve as a barrier that completely nullifies physical attacks?"
"I’m not sure yet. But it’s certainly worth testing."
Jin and Laojun continued to refine the details as they spoke.
＊ ＊ ＊
Magic circles were not a mature enough system to be perfected by theory alone. Experimentation and practical application were essential.
"Alright, let's begin the test."
"Yes, Father."
Jin was about to test the prototype Space Isolation Barrier he had constructed. For the test, the barrier was a disk-shaped field one meter in diameter. The generator required to produce it was roughly the size of a tissue box. While it could be miniaturized further, Jin had kept it this size to make it easier to analyze and confirm its internal operations.
"Wake up."
Reiko and Jin stood about five meters apart. Jin stood directly beside the barrier generator, while Reiko stood in front of it. The plan was for Reiko to launch various attacks at the barrier while Jin observed the results.
"Good, the generation is stable."
A pitch-black barrier appeared in the air.
"It looks black because... it's not emitting or reflecting any light, I suppose?"
Jin surmised that it looked black not only because it emitted no light of its own, but because any light that struck it failed to reflect back. In a sense, it was the same 'color' as a black hole, although this barrier didn't actually suck anything in.
"Right now it's just a disk, but eventually, I'd like to try making it hemispherical or even a full sphere."
"Father, what should I start with?" Reiko asked, interrupting his thoughts.
"Ah, right. First, try throwing a stone at it—just a light toss."
"Understood."
Reiko threw a stone using only one percent of her strength. Even so, the stone flew toward the barrier at a speed roughly equal to a grown man throwing it with all his might.
"Excellent, just as I thought."
The moment the stone hit the barrier, its velocity dropped to zero. It fell straight to the ground, pulled down by gravity, coming to a stand still.
He repeated the test three more times with stones of varying sizes. In every instance, the stones lost all momentum the moment they touched the barrier and dropped to the earth.
"Okay, so far so good. Next, let's try magic."
"Yes... Fireball."
Reiko launched a 'weak' Fireball. The sphere of flames flew straight toward the barrier, only to dissipate into nothingness the moment it made contact.
"I see. Reiko, do it again."
"Yes."
Jin repeated the magic experiment five times.
"Hmm. In the case of magic, I wonder if the 'effect' required to maintain the phenomenon is simply erased?"
However, even with Jin's expertise, the exact reason why the magic dissipated remained a mystery. Reiko, who was powered by magi, could pass through a Warp Gate without issue, and human biological functions like blood flow were similarly unaffected.
"For now, I'll just have to accept it as 'that's how it works.'"
As a man of practical application, Jin decided that the theory could catch up later. For now, he would focus on making the technology functional.
"That's enough for this experiment. I'll start working on the second prototype."
"My Lord, I would like to continue the experiments on my end for a while longer."
"I see. Go ahead then."
Since Laojun had volunteered, Jin gave his permission.
"Thank you. In addition to seeking ways to improve efficiency, I will investigate the free ether consumption rate and the barrier's maximum durability."
"Good idea. Have the Smiths assist you."
"I shall."
＊ ＊ ＊
Satisfied that the initial tests were a success, Jin began looking into further applications.
"If we make it a full sphere, it might become impossible to replenish free ether from the outside... in that case, we can use ethenol or mana cells."
"That would limit the operational time, but it would create an absolutely invincible barrier."
"Yeah. Though the downside is that you wouldn't be able to see outside at all."
Visible light, infrared—it was likely that no form of electromagnetic wave could penetrate it.
"So this is why everything goes dark for a moment when we use a Warp Gate," Reiko remarked, sounding enlightened.
"Yeah, that’s almost certainly it."
Jin recalled the sensation. Even though the interior of a Warp Gate housing was well-lit, there was always a split-second sensation of total darkness the moment the teleportation occurred. It hadn't been his imagination. Reiko, with her superior senses, likely perceived the phenomenon even more clearly than he did.
"Still, if it can function as the ultimate barrier, making it deployable even for a short duration would be incredibly valuable."
"Indeed. Especially since the space vibrations only seem to last for a micro-duration of time."
Laojun's observation gave Jin an idea.
"Is it possible to predict a space vibration?"
If they could foresee it, they could deploy the barrier just a fraction of a second before the vibration hit and deactivate it once the danger passed. If that were possible, they might even be able to protect the entire planet of Ars.
"That is a research avenue well worth exploring from multiple angles," Laojun agreed.
The expectations weighing on Jin's shoulders only continued to grow.