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Everyone
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Everyone
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About this game

must be one is a number puzzle built on a single rule — the one in its name.

A grid of numbers. Four operators. Combine neighboring tiles with arithmetic and collapse the whole board down to a single 1. That's the entire game: all becomes one.

It reads as obvious for about three moves. Then it doesn't.

- One rule, no filler — no twenty-minute tutorial, no menus to dig through. You understand it in seconds and spend the rest of your time actually thinking.
- Always solvable — every stage is generated so that a solution is guaranteed to exist before you ever see it. If you're stuck, that's on you, not the board.
- A climb that keeps widening — early stages stay in single digits; later ones open the range up and the arithmetic gets meaner.
- Free, and quick to pick up. One stage on the train; look up an hour later.

From office-canard — a one-person studio making small, system-first games. If this one gets its hooks in, there are more small games where it came from.
Updated on
Jul 9, 2026

Data safety

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No data shared with third parties
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Data is encrypted in transit
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What’s new

First release. A minimalist number puzzle: combine neighboring tiles with arithmetic and reduce the whole board to a single 1. One rule, always solvable, free to play.
Content rating
Everyone
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App support

About the developer
FIT NEST, K.K.
sato@office-canard.com
2-30-8, MINAMIIKEBUKURO TOSHIMA-KU, 東京都 171-0022 Japan
+81 90-2567-2154

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