Binary Puzzle (Binairo, Takuzu)
A binary puzzle, also known as binairo or takuzu, is a grid you fill with only two digits, 0 and 1. There is no math: three rules and careful logic are enough, and every grid here has exactly one solution. Play online or print the PDF with the answer key.
- No more than two 0s or two 1s next to each other in a row or column.
- Each row and column has as many 0s as 1s.
- No two rows are the same, and no two columns are the same.
Easy Binary Puzzle (6×6)
14 of 36 cells given. The three quick patterns below are enough to solve it.
- No more than two 0s or two 1s next to each other in a row or column.
- Each row and column has as many 0s as 1s.
- No two rows are the same, and no two columns are the same.
Tap an empty cell: 0, tap again: 1, once more: empty. On a keyboard use arrows, 0, 1 and Backspace.
Medium Binary Puzzle (8×8)
16 of 64 cells given. At least once you will need to reason about a whole row or column.
- No more than two 0s or two 1s next to each other in a row or column.
- Each row and column has as many 0s as 1s.
- No two rows are the same, and no two columns are the same.
Tap an empty cell: 0, tap again: 1, once more: empty. On a keyboard use arrows, 0, 1 and Backspace.
Hard Binary Puzzle (10×10)
21 of 100 cells given. At some point you will need to try a digit and follow it until something breaks.
- No more than two 0s or two 1s next to each other in a row or column.
- Each row and column has as many 0s as 1s.
- No two rows are the same, and no two columns are the same.
Tap an empty cell: 0, tap again: 1, once more: empty. On a keyboard use arrows, 0, 1 and Backspace.
How to solve a binary puzzle
Start with the three patterns that work on every grid, and use the slower ones only when those run out.
- Pairs. Two equal digits side by side, like 0 0, must have the other digit on both ends: 1 0 0 1.
- Sandwiches. A gap between two equal digits, like 1 _ 1, must be the other digit, or there would be three in a row.
- Counting. A row of 8 holds four 0s and four 1s. Once it has four 0s, every empty cell left in it is a 1.
- Whole lines. When nothing else moves, pick a row that is nearly full and list the legal ways to finish it. A cell that gets the same digit in every way is solved. This is also where rule 3 helps: a row may not copy a row that is already complete.
- Trial. On hard grids, put a digit in one cell and follow the rules from there. If that leads to a broken rule, the cell must hold the other digit.
Stuck online? The Hint button fixes a wrong cell first. If nothing is wrong, it fills the next cell you can reach by logic and tells you which pattern gets you there.
Questions
Are binary puzzle, binairo and takuzu the same thing?
Yes. They are different names for the same grid of 0s and 1s with the same three rules: no three equal digits in a row, as many 0s as 1s in every line, and no two identical rows or columns.
Does every puzzle have only one solution?
Yes. Every grid on this page and the daily puzzle is checked by a solver that confirms there is exactly one way to fill it, so you never have to guess.
What makes the hard puzzle harder?
Not the number of given digits but the reasoning it needs. The easy grid falls to pairs, sandwiches and counting. The medium grid needs at least one whole row or column worked out. The hard grid needs a trial step: assume a digit and follow it until a rule breaks. This hard grid starts with 21 of its 100 cells filled.
Can I print these puzzles?
Yes. Each puzzle has a Download PDF button. Page one is the puzzle with the rules and a space for your name, page two is the solution. Everything is black and white, so it prints well on any printer.
Is there a new binary puzzle every day?
Yes. The daily binary puzzle changes at midnight UTC. Monday and Tuesday are easy, Wednesday, Thursday and Sunday are medium, and Friday and Saturday are hard.