1. Never three of the same in a row
At most two equal digits may touch, horizontally and vertically. Spot two zeros next to each other? Then both neighbouring squares must hold a one.
Play binary puzzle
Fill the grid with zeros and ones: never three of the same in a row, as many zeros as ones in every row and column, and no two identical rows or columns. Simple rules, surprisingly much to think about. Choose your level below — one tap cycles a square between 0, 1 and empty.
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The three rules
2. As many zeros as ones
Every row and every column contains exactly as many zeros as ones. On an 8×8 board that's four of each — count and cross off.
3. No two identical rows or columns
Every complete row is unique, and so is every complete column. Two nearly finished rows that look alike? Compare them — the difference reveals the last squares.
Every puzzle we generate has exactly one solution and can be solved without guessing. Your progress is saved automatically on your own device.
Prefer a fixed challenge? Play the daily binary puzzle (the same for everyone), dive into the rules and solving techniques, or print binary puzzles as a PDF for on the go.
Frequently asked questions about the binary puzzle
What exactly is a binary puzzle?
A logic puzzle where you fill a grid with only zeros and ones, following three rules: never three of the same next to or below each other, as many zeros as ones per row and column, and no two identical rows or columns. The game is also known under names like Takuzu, Binairo or Binoxxo.
Do I need maths or computer knowledge?
No. The zeros and ones are simply two symbols — no arithmetic or computer knowledge involved. It is all about logical reasoning: looking, comparing and filling in.
Can every puzzle be solved without guessing?
Yes. Every puzzle is guaranteed to have exactly one solution, and on Easy and Medium direct reasoning always gets you there. On Hard and Expert you sometimes need to think a few steps ahead.
How do I fill in a square?
One tap puts a 0 in the square, a second tap turns it into a 1 and a third tap clears it again. With the keyboard you can use the arrow keys, the digits 0 and 1, and Backspace to clear.
What does it cost and do I need an account?
Nothing and no. All binary puzzles are completely free, without an account or download — the site works right in your browser, on tablet and phone too.