The five Mini-Smiths disassembled the wristwatch in a matter of moments.
They soon discovered the culprits behind the malfunction: a chipped gear and a snapped mainspring. Both were minute damages, well within the realm of what could be repaired with Craft Magic.
As the inspection continued, they found that the watch's case was actually chrome-plated, not 18-12 stainless steel. Jin’s initial guess, based on the luster, had been off the mark.
Several characters were engraved on the case back.
"Let's see here..."
Written there was the name of Company S, a seven-digit number that looked like a model number, and "JAPAN."
"I knew it..."
Seeing that familiar name after so long filled Jin with a sense of nostalgia as he gazed at the letters.
Mechanical watches, by their nature, are extremely sensitive to dust. If even a speck of grit gets caught between those precision gears, the movement can falter or stop entirely. For that reason, in the past, assembly was historically done in regions with clean air, such as Switzerland in Europe and the Suwa region in Japan.
In the modern era, they are produced in clean rooms filled with purified air, where workers wear specialized clothing that doesn't shed lint.
But I digress.
Even microscopic dust invisible to Jin was like a mountain of trash to the 1/16th-scale Mini-Smiths. Their ability to manage such things visually was their greatest strength.
Taking great care to ensure no contamination entered the mechanism, they completed the repair and assembly. The solidified lubricating oil was removed, and fresh oil specially formulated on Hourai Island was applied.
The internal gears were brass, and they had escaped corrosion—perhaps due to good storage conditions or some lingering preservative magic. Jin instructed the Smiths to leave the crucial area around the balance wheel—which serves the same function as a wall clock's pendulum—exactly as it was, avoiding any unnecessary adjustments to maintain its original state.
"It's done."
Jin held the watch gently and carefully turned the crown.
"They probably overwound it and snapped the spring."
In older manual-winding watches, it was common for users to accidentally break the mainspring by winding it too tightly. Jin hadn't known that specific detail, but after examining the structure, seeing the break, and hearing the report from the Mini-Smiths who serviced it, he had arrived at that conclusion.
"Oh, it's moving."
With a faint tick, tick, tick, the second hand began its circuit.
"Right. If I use this, I can figure out if a day on Earth is the same length as a day here."
Even if the units shared the same names, it didn't mean the actual duration was identical. For example, an hour on Earth might be 59 minutes and 45 seconds on Ars. While the difference certainly wasn't large enough to be felt instinctively, there was no guarantee they were an exact match. Jin realized that this watch would allow him to make a direct comparison.
"I can have Laojun verify it."
Hourai Island currently used a clock based on the sun of the Ars world. It could measure down to the minute, but it lacked the precision to track seconds. Jin hoped that if there was no major discrepancy between a "second" on Earth and on Ars, he could use this wristwatch as a template to mass-produce small timepieces.
Of course, this assumed the wristwatch hadn't lost its accuracy over a thousand years, but that was what the experiment was for.
＊ ＊ ＊
"Onii-chan, dinner's ready!"
Hanna came to find him, smelling faintly of soap after her bath. Jin, who had been completely absorbed in the watch, snapped back to reality.
Beside him, Reiko looked a little dejected.
"Father, I am sorry. I was so focused that I failed to notice the time. I have done you a disservice."
Jin offered her a reassuring smile.
"Don't worry about it. This wristwatch is worth far more than one missed bath."
Turning toward the door, he called back to the girl waiting there.
"Coming, Hanna!"
Dinner was served with the Bailiff, Fadon.
Seated next to Goose was a girl who looked to be roughly the same age as Hanna. She was snuggled up close to him, looking very affectionate, but Goose himself appeared somewhat drained. Jin surmised that the Bailiff’s granddaughter had taken a liking to him, and he’d been dragged along to dinner. It seemed Goose wasn't particularly good with children.
The meal consisted of white rice, miso soup with turnip-like vegetables, salted grilled river fish, smoked meat seasoned with salt and pepper, and pickles.
"Oh, smoked meat!" Hanna exclaimed.
Jin had made smoked foods back in Kaina Village, but it appeared the technique existed here as well. Fadon asked if it was to their liking, and the dinner proved to be quite delicious.
"So, Lord Nidou, how goes the work?" Fadon asked after the meal while they sipped hojicha. Naturally, he was asking about the wristwatch.
"Yes, it looks like I'll be able to fix it," Jin replied, causing Fadon's face to light up with a broad smile.
"Truly? Oh, that is wonderful news!"
"Please look forward to tomorrow," Jin said, and Fadon nodded happily over and over.
As they were returning to their rooms, Elsa leaned in and whispered.
"...Jin-nii, is it actually already fixed?"
Jin gave a wry smile and a silent nod. Elsa nodded back, looking vindicated.
"I'll come by later," she said before heading into her room.
Jin entered his own room, where the Mini-Smiths were still monitoring the watch's performance.
"MASTER, IT IS OPERATING NORMALLY," one reported in its high-pitched, squeaky voice.
"Good work. And? Did you find the time difference?"
Reiko answered in their place, having already received the data from Laojun.
"Father, since only an hour has passed, the margin of error is still significant, but it appears a second in this world is slightly longer than the one recorded by this watch."
"I see. Interesting. Carry on."
Just as they finished their report, there was a knock at the door. Reiko immediately turned invisible. Although the room was decorated in a Japanese style, the entrance was a standard door rather than a sliding one.
"Jin-nii." "Jin." "Jin." "Onii-chan."
Elsa, Goose, Saki, and Hanna had all come to see him. The girl who had been clinging to Goose was nowhere to be seen.
"Goose, where's the little girl?" Jin asked.
Goose let out a weary laugh. "The Bailiff’s granddaughter. I helped her with some studies a while back, and ever since then, she won't leave me alone..."
It was exactly as Jin had suspected. The Bailiff had been quite pushy about inviting Goose for that very reason.
"Anyway, we want to see the watch in motion," Goose said, clearly trying to change the subject.
"Sure, go ahead. It's right here."
Jin pointed to the low table. "Just don't touch it, okay?"
The Mini-Smiths had already hidden themselves.
"Wow, it's really moving!" Goose marveled as he leaned in to look.
"...This is a first for me. How interesting," Elsa said. While she knew the theory, this was her first time seeing a real clock, and she looked fascinated.
"Hehe, so this is a watch? To think it can measure down to the second... that's incredible," Saki added, impressed by its utility.
"Does this have an escapement too?" Hanna asked.
The question caught Jin off guard. An escapement is the mechanism essential for making a mechanical watch run at a constant speed. By using the regular rhythm of a pendulum, it catches a gear—specifically the escape wheel—with two claws on a part called the pallet fork, releasing it one tooth at a time.
In a wristwatch, the pendulum is replaced by a part called a balance wheel—often called a regulator—which performs the same role through reciprocating rotation.
Descriptions and simple diagrams of this had been in the History of Technology they found in Romune Village. Hanna had clearly absorbed and understood that information. Her level of comprehension was staggering.
"You're incredible, Hanna. A total genius..."
Jin felt a genuine desire to see just how far Hanna's talent could take her.