Chapter 23:

Ch.2 – EP23 Quiet Mate (Keita vs. Rei)

Caïssa’s Child: The Boy Who Beat the AI

The announcement glides across the venue’s ceiling.

“Next board—last year’s champion, representing Kanagawa Prefecture: Rei. Versus representing Nagano Prefecture: Keita.”

The press seats stir; long lenses swivel in unison.

“He’s here, last year’s champion.” “Rumored to be undefeated in Japan.” “ELO 2250 versus ELO 2010. How far can Keita hang on…?”

Rei ties his black hair back, pulls out his chair with efficient, spare movement. His gaze is quiet, as if he even notices the disturbance of light falling across the board.

Across from him, Keita moistens his dry lips with his tongue and takes one deep breath.

(I’ll do it. Whoever the opponent, I’ll do it. —I’ll just place my one move.)

The arbiter gives a slight nod, and the clock is pressed.

____________________________________________________________________________________

【Opening: A cool overture】

1. b3—with White, Keita begins with Larsen.

“Oh? A sidestep from the main roads.” “A b3–Bb2 long-range setup.”

Rei replies at once with …e5, planting a stake in the center.

2. Bb2 Nc6 3. c4 Nf6 4. Nf3 e4 5. Nd4 Bc5

White’s bishop peers at the black king’s shadow from b2; Black steps forward with e4.

“Confident.” “A struggle for the initiative.”

6. Nxc6 dxc6 7. e3 Bf5 8. Qc2 Qe7 9. Be2 O-O-O

Rei masticates the opening, calmly. Exchanges are no more than necessary; pawn moves are the bare minimum.

From quick castling, Keita draws a picture aimed at central pressure. (I can go for it—not bad. We’re meshing.)

10. f4

Keita’s finger pushes the f-pawn.

(Go. The initiative is on my side!)

Rei hops in with …Ng4, putting kingside pressure.

“Quietly preparing the attack.”

At this point the engine’s evaluation posts −2.9, spitting out Black’s overwhelming advantage.

____________________________________________________________________________________

【Middlegame: Soundless pressure】

11. g3 h5 12. h3 h4

White shores up the diagonal with g3; Black rams the h-pawn two steps.

“He’s going to stab.” “It’s getting brutal.”

13. hxg4 hxg3

—White’s h-pawn bites off the piece on g4 (Black’s Ng4), and Black’s h-pawn smashes back to g3.

The piece sounds are small, yet the spectators hunch their shoulders.

“Whoa.” “Close-quarters fighting.”

14. Rg1 Rh1

White’s rook eyes the g-file from g1, and Black’s rook slides to h1.

Light breaks across Keita’s eyes. (We can trade blows here! If he takes, I advance; if he doesn’t, the pressure mounts.)

15. Rxh1 g2

White Rxh1 cuts down Black’s rook. In that instant, Black’s g-pawn steps in to g2.

—The temperature on the board rises by two degrees.

“It’s through.” “Smells like promotion.”

Rei’s face doesn’t change.

White’s Keita, deep in his chest, beats out a drum.

(From here—I’ll finish.)

____________________________________________________________________________________

【Climax: moves 16–20, quiet mate】

16. Rf1 Qh4+

The black queen comes to h4. Check.

On the spectator display, the eval bar plunges to −∞ in a single breath.

The commentator’s voice drops without carrying any breath.

“…This is already mate. The only one who hasn’t noticed is the player himself.”

A line of sweat runs down Keita’s forehead.

(No way—no, there’s still a king escape—)

17. Kd1 gxf1=R+

The moment White’s king flees to d1, Black’s g-pawn captures on f1 and promotes—to a rook. And it’s check.

Promoting to a queen would also win, but Rei prefers shortest and waste-free; a rook promotion is sufficient.

Cameras push in on Keita’s profile; shutters click, restrained.

18. Bxf1 Bxg4+

White’s bishop cuts down the newly promoted black rook.

Rei immediately plays Bxg4+—reaping White’s h-pawn that had stepped to g4 a moment ago, with check.

The board’s breathing stops once there.

19. Kc1 Qe1+

White’s king goes to c1. Black’s queen presses forward one notch to e1+, like pushing a door in.

A few spectators cover their mouths. (Ah… Qd1.)

20. Qd1 Qxd1#

—No sound.

Even the sound of the pieces seems absorbed.

The black queen bites off d1.

Checkmate.

Applause arrives late.

First distant, patter, patter. Then the wave spreads.

But at the center, it’s still quiet.

“Quiet mate”—everyone in the hall recalls those three characters at the same time.

At last, words drop into Keita’s chest.

“Eh… No way, I was already dead…?”

It isn’t self-mockery. Understanding just caught up late.

____________________________________________________________________________________

【Afterglow: The board’s temperature】

The clocks stop. Rei quietly pushes in his chair and gives a small bow.

He doesn’t meet his opponent’s eyes.

—His bow is to the board. That’s Rei’s etiquette.

The commentary desk resumes its whisper.

“Last year’s champion: truly otherworldly. The unruffled tailoring from b3, the preparation with f4, the h-file contact sequence that never becomes noise.

And from 16…Qh4+, the machine-like conversion—this is quiet mate.”

Reporters’ pens race.

The PGN records only the shadows of the moves with precision.

For those who want to check how the pieces move, copy the section from <PGN> to </PGN>, paste it into the PGN input field on Lichess’s analysis board (https://lichess.org/analysis), and press the Import button.

(Nothing sticks out. Nothing thrashes. Even so, it’s a mate where there’s no sound, yet only your heart races.)

Keita exhales softly and signs the scoresheet.

He’s frustrated. And yet even that frustration has its shape in order. (He was strong. Perfect.)

While resetting the pieces to their initial squares, Rei pauses his fingers ever so slightly.

Qe1–Qd1—he traces a line in his mind.

Then, as if nothing had happened, he vacates the seat for the next players.

The crowd flows on.

“First round had Sandra’s ten-move mate, and now Rei’s twenty-move quiet mate.” “Two extremes of the north visible in today’s nationals.”

“If they meet in the final, it’s Ice vs. Quiet.”

“Before that—what will our first-year do?” Sōma grins.

Between the laughter and the sighs, a modest tension remains.

Some speaker somewhere reads out the next pairings, and new clocks are pressed at boards across the hall.