It was the night before the storm.
The window of Spice’s workshop always carried the unwavering glow of its light bulb, but that night alone, a faint pale-green light flickered alongside it. A wind carrying the scent of the rainy season drifted in from the direction of the crossing, and the bottles lined up deep in the workshop’s drawers rang quietly.
It was that morning that Spice finished the predictive machine he’d named, himself, “the Demon’s Abacus.” Combining six hundred and thirty-seven parts, he had implemented an algorithm to calculate every movement in Amencho Town. He was trying to give form, in metal and current, to a theory once dreamed up by a man named Laplace — that an intelligence which knew the position and velocity of every atom in the universe could calculate both the past and the future entirely.
“At 3:14 p.m., Kopo will trip on the third step of the stone bridge. Margin of error: plus or minus 0.7 seconds.”
The machine output that. Kopo said “no way,” crossed the bridge, and, precisely on the third step, caught his foot and let out a shriek toward the water’s surface. Soaked, he came back saying “fluke,” but his voice was a little too high.
The machine went on predicting , one after another. The timing of Sonchō’s “Feh-feh” laugh. The exact weight of the vegetables in the cart Mocchi pulled. The third note of the next melody Keromi would hum. All of it came out with unerring accuracy.
Kopo stood silent for a while in the corner of the workshop.
“Kind of unsettling. Knowing I’ll trip before I trip.”
Spice said nothing and kept entering the next parameters .
That evening, when Kopo asked, “So what’s it saying about Dragon God’s Lake?” Spice silently pointed to the screen.
Nothing was displayed there. Not an error, not a blank. The calculation’s gears simply kept turning without stopping, and only the output stayed forever delayed.
“…Only the part about the Dragon God won’t finish calculating.”
“Why not?”
“Every possibility exists with equal probability . It can’t decide which one is correct.”
As Spice murmured that, the stone lamp at the edge of the workshop shelf flickered pale blue for an instant. There was no such command in the program. Kopo, still dripping water, peered at the screen.
“…Maybe it’s not that it won’t finish.”
There was a pause.
“Maybe it doesn’t want to finish.”
Spice said nothing. The next morning, the Demon’s Abacus once again accurately predicted every event in Amencho Town, but the calculation for Dragon God’s Lake is still running, even now. What that means, Spice still hasn’t managed to write into a paper. When Kopo said, “try running how many times I’ll trip tomorrow,” Spice paused his input just once, then turned back to the screen. That answer, in the end, was never output.
Margin note: What the Demon’s Abacus predicted most precisely of all was “the day Spice doesn’t stop the calculation for Dragon God’s Lake.” It hasn’t been wrong yet — not today, not tomorrow.
【Core of the Tale】
- Phenomenon used: Dragon God’s Lake’s “uncomputable domain ” (a new phenomenon ), the pale-blue flicker of the workshop’s stone lamp
- The story’s hidden theme: in a world entirely governed by determinism , only the Dragon God’s sanctuary functions as a refuge for “free will”
This is an English translation of “悪魔の算盤”, part of Tales of Amencho Town (蛙鳴町奇譚).