Queens Puzzle — Free to Play, and How It Works
A Queens puzzle is a colored grid with one hidden arrangement of queens, and your job is to find it by logic alone. The one above is ready to play — free, with no login — and when you finish it, the New puzzle button makes another. The rest of this page looks at the puzzle itself: what a board is made of, why it can always be solved without guessing, and what makes one board harder than another.
Anatomy of a board
Every board is a square grid, N cells on a side, cut into exactly N colored regions. The regions are irregular: some sprawl across half the grid, others are two or three cells tucked into a corner. Hidden in the grid are N queens (drawn here as crowns), placed so that each row, each column and each region has exactly one, and no queen touches another, even at a corner. You are never shown a queen at the start. The colors are the only clue, and they are enough.
That last point is what gives the puzzle its character. In Sudoku you start from given digits; here you start from shapes. A long thin region tells you something different from a fat square one, and learning to read those shapes is most of the skill.
Why there is always exactly one answer
A grid of colored regions drawn at random will usually allow several valid arrangements, or none at all. Such a grid is not a fair puzzle, because at some point you would have to guess. So every board on this site goes through a solver before you see it. The solver counts the valid arrangements, and the board is kept only if the count is exactly one. When it is more than one, the generator reshapes a few region borders and tests again.
For you as a player, that guarantee has a practical use: if you reach a contradiction, the puzzle is not broken — one of your earlier marks is wrong. And if you feel stuck, there is a forced move on the board that you have not seen yet. The Hint button will show you where.
What makes one Queens puzzle harder than another
- Size. A 6×6 has six queens to find and usually gives one away at once. A 10×10 has ten, and far more cells that look possible for far longer.
- Region shapes. Tiny regions and regions confined to a single row or column make for a quick opening. When every region is large and spread out, nothing is forced at first and you have to combine clues.
- The depth of the first step. On easy boards each move follows from one region. On hard ones the opening move comes from looking at two or three regions together — for instance, noticing that two regions both fit only inside the same two columns, so no other region may use those columns.
The four sizes here are labelled to match: 6×6 easy, 8×8 medium, 9×9 hard and 10×10 expert. The daily board moves through the sizes during the week, from 7×7 on Monday to 10×10 on Saturday.
Not the chess problem
The name causes some confusion. The famous chess exercise of placing eight queens on a chessboard so that none attacks another is a different thing: it has no colored regions, many solutions, and queens that attack along whole diagonals. In the puzzle on this page a queen only blocks the eight cells right around it, and the colored regions do the work that long diagonals do in chess. If you came looking for the chess version, this is not it — though you may well like this one more.
A good first ten minutes
- Set the size menu under the board to Easy · 6×6 and find the smallest region. If it has one cell, that cell is a queen.
- Place it and watch what Auto-✕ crosses out: the row, the column, the rest of the region and the ring of cells around the queen. Then look for the region that now has the fewest open cells.
- After two or three wins, move up to 8×8. When an 8×8 stalls, read the strategy guide; it names the patterns you are missing.
The complete rules and controls are on the Queens rules page. Unlimited mode is the same endless supply of boards as above on a page of its own, and every earlier daily is kept in the archive.