The day after the party, Jin traveled to Onogoro Island with Marikka.
"Welcome, Lady Marikka."
Testa, the Supervising Brain, greeted her.
"I-I've come today because there is something I wanted to ask."
"Please, ask whatever you wish."
"Jin-sama will explain the details."
"...Actually, space vibrations have been occurring for the past few days..."
Jin recounted the situation, explained the dangers, and shared his theories. "Do you have any records of this, or have you discovered anything?"
"How ish... is it?" Marikka added.
"There are no records of any such phenomenon, Lady Marikka."
"I see..."
"I apologize for being unable to be of assistance."
The brain further explained that because Onogoro Island was primarily dedicated to managing Planet Ars, it did not conduct surveillance of outer space.
＊ ＊ ＊
"I'm sorry, Jin-sama."
On the way back, Jin comforted the dejected Marikka.
"No, look at it this way—it proves that this isn't a common occurrence. So, cheer up."
"...Thank you very much."
After seeing Marikka and Sion off to the Nord Federation, Jin once again immersed himself in his research.
Given the gravity of the threat, Elsa found it difficult to tell him not to overwork himself. Instead, she devised a plan.
"Hanna-chan, could I ask you to act as Jin-nii's assistant?"
"Yeah, I'd love to!"
Elsa reasoned that since Jin had a soft spot for Hanna, he wouldn't push himself too hard. Furthermore, she believed Hanna's unique perspectives would surely be of use to him.
The plan was a resounding success.
"Onii-chan, it's almost time for lunch."
"...Ah, is it? Alright, let's take a little break."
Jin obediently stopped his work and stood up. Reiko watched the exchange with a gentle smile.
"Jin-nii, perfect timing. Lunch is just ready."
When they reached the dining room, Elsa and Mine had just finished setting the table. Today's menu was mori-soba, served with freshly fried tempura.
"Elsa, are you okay with the smell of the oil?" Jin asked, concerned about her morning sickness.
"Mmh, I'm fine today. Besides, Mother fried the tempura for me."
"Yes, that's right," Mine added. "And it seems she does better when she eats small amounts throughout the day, rather than sticking to three square meals."
Since eating until full could exacerbate morning sickness, Mine's suggestion was proving effective for Elsa.
"Juice made from Persica, citran, or apulul seems to help as well."
The fruits grown on Hourai Island were exceptionally nutritious. Consuming calories through juice while keeping solid foods to a minimum was proving to be a viable strategy.
"I feel much better thanks to all that."
"I see. I'm glad to hear it."
Jin finished his serving of mori-soba, while Hanna slurped her noodles down with gusto.
"This is delicious!"
"I'm glad you like it. There's plenty for seconds."
In the end, Jin had three helpings and Hanna had two.
As a side note, it is said that at certain soba shops, they prefer customers to order refills rather than one large portion. This ensures the aroma of the buckwheat doesn't dissipate and the noodles don't lose their firm texture.
"Thank you for the meal."
After finishing with the soba-yu, they relaxed with a cup of buckwheat tea. While sipping her tea, Elsa turned to the others.
"How is the research coming along?"
Jin took a sip before answering. "Well, it's... going okay, I suppose?"
He explained that the Space Isolation Barrier was progressing reasonably well. "The efficiency is more than double that of the prototype, and I have a clear path toward deploying it in a hemispheric shape."
"That's good to hear."
"But the problem is that we can't predict the space vibrations at all."
"Exactly," Hanna added with a weary sigh. "The biggest issue is that we just don't have enough data."
"That is a problem."
"As a fallback, I'm considering a system that deploys the barrier the instant a vibration is detected. However, I can't get the reaction speed faster than one ten-thousandth of a second..."
"I suppose that's quite difficult."
Jin believed the system would be meaningless unless it was at least an order of magnitude faster—it needed a reaction speed of at least one hundred-thousandth of a second.
"I know it's theoretically possible, though."
"Wait, really?" Elsa was stunned. She couldn't even imagine how one would measure such a minuscule span of time.
"In the world I came from, there was a realm of nanoseconds... one-billionth of a second."
"A billion!?" Elsa's eyes went wide.
"I believe it's possible even with ether waves. However..."
"Is there a problem?"
"Yeah..." Jin's expression turned grim. "To make the reaction that fast, the components have to be incredibly small. But if they're that small, they can't generate a wide-range barrier."
As he spoke, a flash of inspiration hit him. "A relay...!"
"A relay?"
"Onii-chan, what's a relay?"
Neither of them recognized the term. Even for Jin, his knowledge was limited to having replaced them during system maintenance in his past life.
"Well, a relay is a component used to control a large output using a very small signal."
"...So, you make the detection part small, and the barrier generator large? And then you connect them with this 'relay'?" Elsa phrased the concept in more concrete terms.
"But won't adding a relay in the middle slow down the reaction time?" Hanna voiced her concern.
"True, but as long as the combined reaction time of the detector and the relay is short enough, we should be able to make it work."
"Oh, that makes sense!"
"I'm convinced."
"Let's start the experiment right away."
＊ ＊ ＊
Jin headed straight for the workshop, with Hanna and Elsa following close behind—though Elsa was strictly there to observe.
"I'm actually feeling quite good right now," she said. Her morning sickness seemed to be staying at bay for the moment.
"Alright. I'll need the help of the Little-Smiths for the micro-scale work."
Little-Smiths were small golems, only forty centimeters tall. Their size made them experts at precision tasks.
"...I want to build something like this. I'm counting on you."
"YES, MASTER," the Little-Smith replied in its characteristically high-pitched voice. It immediately set to work.
Since these were magical components rather than mechanical ones, the work primarily involved the Write In process on magi-crystals.
"IT IS FINISHED."
"Good work."
The necessary Write In was completed in under a minute.
"Okay. This is the detection unit, and this part acts as the relay. Now, I'll attach the Space Isolation Barrier generator I finished earlier to it."
Jin handled this part of the assembly himself.
"The prototype is done, but we can't test it in here..."
Since indoor testing was out of the question, they took the prototype out to the garden in front of the laboratory.
"This should be a good spot." Jin set the device down. "The barrier is configured to generate ten meters in diameter, five meters above the unit."
But then, Jin realized a fundamental flaw.
"How am I going to measure the time between the detection stimulus and the barrier actually forming...?"
It wasn't going to be that simple. The group fell into deep thought once again.