Just Yin Yang · Just Play

Fill an 8×8 board with ● and ○ under three small rules. No ads, no streaks, no daily quests.

Just Yin Yang is a quiet take on Binairo (also known as Takuzu) — a logic puzzle played on an 8×8 grid with two symbols, ● and ○.

Three small rules govern the whole game:

1. Every row and every column ends up with exactly four ● and four ○.
2. The same symbol cannot appear three times in a row, across or down.
3. A small mark between two cells means they must be the same (■) or different (◩).

That's it. The rules are small. The space they open up is not.

WHAT'S INSIDE

— 800 hand-rated puzzles, from gentle Beginner to true Expert. — Eight difficulty tiers, each tuned by the deepest logical technique it requires — Triple Avoidance, Count Saturation, Constraint Propagation, Gap Filling, Row/Column Pattern, One-Step Lookahead, and beyond. — Played a puzzle? It's gone — you won't see it again until you've worked through the whole tier. — After every win, two taps: same level again, or step up.

DESIGNED TO DISAPPEAR

Just Yin Yang is a quiet app. The interface is warm and paper-soft, in the spirit of Chinese calligraphy paper. Black stones for 阳, hollow stones for 阴, and the few controls you actually need.

It looks the same on day one as it does on day one hundred.

PLAY YOUR WAY

— Tap a cell to cycle: empty → ● → ○ → empty. No separate buttons to fumble with. — Three hints per puzzle. Each one fills in a cell you could have deduced. — No lives lost for stray taps — only an actual rule break is flagged. — Soft haptics that confirm your touch without shouting.

PRIVACY BY DEFAULT

Just Yin Yang does not collect any personal data. It works completely offline. There is no account to create, no email to enter, no servers to talk to. The puzzles live on your device.

FULLY LOCALIZED

Available in: English, 简体中文, 繁體中文, 日本語, 한국어, Español, Français, Deutsch, Italiano, Português (Brasil), Русский, العربية.

For people who love the puzzle itself.