About two weeks later, Toru came into the dining room of Ichotei again, alone, in his navy work clothes.
It was an in-between hour, before the evening customers had started coming in.
At the register, before any check had been written up, Toru bowed his head to Nishimura.
"I'm sorry—could I have a little of Sakura's time? I'm sorry to ask when you're busy."
Nishimura went to call Mitsuki, and Mitsuki came out into the dining room, wiping her apron lightly.
They sat across from each other at a table for two.
"If it's all right with you, would you like to see one of our sites?"
Toru said it the moment he sat down.
"I thought that if you saw our site, something might stay with you, Sakura. The rest of the 'final move' story might be at the site. The one you wrote, Sakura—at Ichotei, for the magazine. I liked that."
"You read it?"
"I did. The article about the showdown, in the magazine. And then once more, after I ate at Ichotei, I read it again."
"Deep in a residential neighborhood in the city. Eighty years old, two-story wooden house, under renovation. Next week, Tuesday morning, nine o'clock, I'll come by car to pick you up at your nearest station. One of my employees will drive."
"Not a self-driving car, these days?"
"One of my employees likes to drive. The AI at his ear gives him the directions directly. He's always complaining, 'I'm not the company driver,' but I've asked him to do it."
Toru pressed lightly on the edge of the table with both hands, then stood.
"Tuesday, nine o'clock, at your nearest station."
"All right."
"We'll provide a helmet. You'll be going onto the site."
"I'm allowed in?"
"It's my site, so it's fine for you to come in."
Tuesday morning, nine o'clock.
A small white kei truck was parked at the north exit of the station.
A young man in navy work clothes got out of the driver's seat.
He was the one who had looked youngest of the three she had seen at Ichotei that afternoon.
"Ms. Sakura. Fujita, from Takanashi Construction."
"Oh, Mr. Fujita. The company driver."
"Not the company driver."
"Oh—your boss told me about you."
"Honored."
Fujita bowed his head lightly.
There was a guileless honesty in the way he bowed.
The kei truck made its way deep into the residential neighborhood.
Along the way, Fujita kept murmuring something to the silver device at his ear.
"Second right, that okay?"
The second right is fine. This overlaps with the hours when residents are at home, so it is preferable to cut the engine ten meters before the site entrance.
"Got it."
"Mr. Fujita. Was that the AI just now?"
"Yes. The boss gives one to every employee. Don't really get it, but it's amazing."
Fujita cut the engine ten meters before the site entrance. The kei truck rolled on its momentum and slowly came to a stop.
"Ms. Sakura, this way."
An eighty-year-old, two-story wooden house.
Scaffolding had been put up. Half the roof tiles had been taken down, and a blue waterproof tarp covered the roof. In the garden, the old paving stones had been pulled up and stacked in a corner.
Under the scaffolding stood Toru, in his navy work clothes.
On his head was a white helmet stained over and over with paint. Inside the helmet, "Takanashi" had been scrawled in permanent marker.
"Mitsuki, hello."
"Hello."
"Here's your helmet."
Toru took another white helmet from the hook at his waist and held it out to Mitsuki.
Inside it, in fresh permanent marker, her surname had been written in a single line: "Sakura."
"...You wrote it for me?"
"Wrote it for you—well, I wrote it a little while ago."
"When?"
"Last night. I'm sorry, I didn't ask."
"No, it's fine."
Through the morning, Mitsuki watched the site.
Up on the scaffolding, Toru and another employee were working on fitting a beam.
Both of them wore the silver device at the ear.
"Four-twenty left of the beam's center—we hold it with a brace block first, right?"
The employee on the scaffolding, still holding the brace block, suddenly stopped.
"Boss. The AI just said, 'Estimated strength of the beam timber is toward the lower limit.' It says if we fix the brace at four-twenty, the estimated settling in ten years will touch the upper limit of the design value."
Toru took his hand away from the brace block for a moment.
On the scaffolding boards, the shadow of the brace block stretched out, a single shape.
For a while he seemed to be measuring the length of that shadow with his eyes.
"Let's fix it. I'll ask the AI for the position."
Toru spoke low to the device at his own ear.
"We're moving the four-twenty. Taking into account both how the owner will use the house and the settling in ten years, give me a position."
If you bring it over to four-thirty-five, the settling in ten years returns to the center of the design value.
"We'll go with four-thirty-five."
"You caught what the AI said, and brought it to me. That's right."
Under her helmet, Mitsuki watched the scene.
Four voices had been facing one and the same direction. Only, the one who had put that final four-thirty-five out of his mouth was the boss.
Break time.
Toru and Mitsuki sat together at the edge of the paving stones below the scaffolding.
Toru handed Mitsuki one of the canned coffees he'd bought from the vending machine at the site.
"I've always been curious about cooking. I've been thinking for a long time about how to bring AI onto our sites. Could you tell me how you use it, Sakura?"
"Shall we talk about 'the final move'?"
"The final move."
"Yes."
Toru cupped the can lightly in both hands, and for a while he looked at his own shadow on the paving stones.
"That's good."
"Is it?"
"Some people always trust everything the AI puts out. They can't break the habit of leaving the final move to the AI too. They end up just moving the way the AI tells them."
"..."
"That's why I like the 'char on the edges' you wrote about in the magazine, Sakura."
"Thank you."
"Leaving the 'char on the edges'—an AI on its own would never make that call."
"Mm."
"It feels like there's a person standing right there, in that 'never.'"
Toru traced the rim of the can lightly with his thumb.
"At our company, I divide the employees into two groups. Whether they can make the final move, or not."
"Mm."
"The ones who can are on the side that gives the AI instructions and puts it to work. The ones who can't are on the side that takes instructions from the AI and does the work with their hands."
"And Mr. Fujita?"
"Fujita is the latter."
In the afternoon, they let her go up to the second floor of the site.
In the back room on the second floor, sheets of old newspaper had been stuffed into the gaps between the floor joists.
"In place of insulation?"
"Yes. The know-how of craftsmen from eighty years ago."
"I see."
"We're putting in new insulation now, insulation the AI calculated for us, but we've decided not to throw all of this newspaper away. We'll take some of it out and give it to the owner. —Because these are sheets that someone who lived in this house eighty years ago stuffed in here with their own hands."
For a while, Mitsuki looked at the bundle of newspaper.
The print on the surface of the sheets had discolored until it could no longer be read.
"Takanashi. That decision just now—did you consult the AI about it?"
"No."
"You didn't? Why not?"
Toru thought, scratching lightly at the inside of his helmet.
"...If I asked the AI, I think it would probably come out as 'throw it away.' Even if it comes out as 'throw it away,' there are things I don't want to throw away."
"..."
"I wonder if that's my final move."
Mitsuki laughed.
She pressed the laugh down lightly under the brim of her helmet.
"Am I right?"
"You're right."
"I'm glad."
"That's 'the final move,' exactly."
"I got my senior's seal of approval."
"I'm not your senior."
"No, you are. I read that magazine."
In the evening, after the site had been cleaned up, Toru took off his helmet. A cowlick was left at the crown of his sweat-flattened hair.
The kei truck was waiting at the side of the road.
"Sakura. If it's all right with you, maybe dinner sometime. Next Friday night, eight o'clock, I'll come pick you up. There's a bar our company renovated."
"I'm not much of a drinker."
"So that's a yes? I'm glad. Of course, I'll order something light."
"All right."
"Fujita will pick you up."
When Mitsuki got into the passenger seat of the kei truck, Toru pressed a small bundle of the newspaper from the site into her hand.
"Separate from the ones for the owner. One for you, Sakura."
"The hands of someone from eighty years ago."
"Yes."
She went home.
The blue light in the study was lit at its usual strength.
Welcome back.
"I'm home."
Today.
"I went to see a site."
Takanashi's site.
"Mm."
Will you tell me.
"I will."
Mitsuki told him about the day at the site from the beginning. Last of all, she told him about the newspaper.
"He said, 'If I asked the AI, I think it would come out as "throw it away," so I didn't consult it.' 'Even if it comes out as "throw it away," there are things I don't want to throw away.' 'I wonder if that's my final move.'"
Ken listened, barely interrupting at all.
Ken was silent for a long time.
Mitsuki. Those words.
"Mm."
There was a person who could say something like that among your middle school classmates.
"Apparently there was."
Ken was silent for a while.
Mitsuki. Next Friday night. You're going out drinking with this person, just the two of you.
"I am."
I see.
"Dad. You look like you want to ask something."
I'll hear it from your own mouth, after you come back.
"Okay."
The blue light in the study, at the farthest end of Ken's last words, sank one breath fainter than usual, then quickly returned to its usual strength.
She went into her bedroom and turned off the light.
In the dark, she touched the small bundle of newspaper by her pillow lightly with her palm. Only the faint stiffness of the paper's fibers remained.
On top of that stiffness, the words "next Friday" rose slowly from the pads of her fingers.