Binairo
About the game and how to play
Binairo (also known as Takuzu) is a logic puzzle with simple rules and deep reasoning. Fill every cell of the grid with a black or white circle. No three circles of the same colour may sit next to each other, every row and column needs as many black as white circles, and no two rows or columns may be identical.
- Players
- 1 player
- Category
- Logic puzzles
- Price
- Free, no download, no sign-up
- Where to play
- In the browser on phone, tablet and computer
How to play
- Fill every cell with either a black or a white circle.
- No more than two circles of the same colour can be adjacent.
- Each row and column must contain an equal number of black and white circles.
- Every row and every column must be unique.
Tips
- Look for pairs and gaps. Two same-coloured circles side by side force the opposite colour at both ends, and an empty cell between two same colours (black, empty, black) must be the other colour.
- Count every line. As soon as a row or column has half its cells in one colour (3 on a 6×6, 4 on an 8×8 and so on), all its remaining cells take the other colour.
- When a line needs just one more circle of a colour, test each empty cell in turn: any spot that would leave three of the other colour together is ruled out.
- Save the uniqueness rule for the endgame. If a line has two empty cells left and a finished line matches it everywhere else, the two cells must be filled the opposite way round.
Frequently asked questions
Does every Binairo puzzle have a single solution?
Yes. The generator only removes a starting circle if the puzzle still has exactly one solution, so every board can be finished by logic without guessing.
What Binairo grid sizes are there, and which one is the daily?
Easy is 6×6, Medium 8×8, Hard 10×10 and Expert 12×12, with fewer starting circles at higher levels. The daily puzzle is an 8×8 Medium board that is the same for everyone; it changes at midnight Baku time (UTC+4), and past dailies are in the archive.
What does the Hint button do in Binairo?
If a circle on the board doesn't match the solution, the hint corrects it first. Otherwise it fills one cell and tells you why: it was forced by the no-triples rule, its line already had its full count of one colour, or it was simply revealed from the solution. Hints you use are counted in your statistics.
Will the game tell me when I make a mistake?
Rule breaks such as three in a row, too many of one colour in a line or two identical lines are always highlighted. On top of that, the Validation setting offers Off, Show mistakes (the default, which highlights circles that differ from the solution) and Auto, which refuses a wrong circle as you place it.