Queens rules
Queens is a logic puzzle where you place queens on a colored grid. The rules read in a minute and apply to every size, from 6x6 to 9x9.
Queens in 60 seconds
The grid is split into colored regions, as many colors as rows. Your mission: place a queen in each row, each column and each region, with no queen touching another queen, not even diagonally. A single arrangement satisfies all these rules at once, and that is the one you are looking for. No luck involved: everything is deduced.
The rules in detail
Four constraints govern every grid. The first three look alike: a single queen per row, per column and per region. The fourth, the contact rule, is the one that trips up beginners the most.
One per row, column and region
Count the rows of the grid: that is the number of queens to place. Each row gets one, each column gets one, and each color gets one. These three counts always line up at the same time when the grid is solved.
No queen touches another
Around each placed queen, the eight neighboring cells become forbidden, including the four diagonal corners. This is the only contact interaction: two distant queens on the same diagonal do not conflict. Just remember that no queen ever sits next to another.
Strategies to start well
You never start a grid at random. The right reflex is to look for the strongest constraint and resolve it first, because each placed queen eliminates many others.
Look for the forced cell
Spot a row, column or region where only one cell is still open: its queen is certain. A small narrow region, wedged into a corner, often offers that first free move that unlocks the grid.
- Handle first the regions that span a single row or column: they lock that line against every other color.
- After each queen, immediately mark the cells it forbids. A well annotated grid makes the next forced cell appear on its own.
- Count regularly: if only one candidate cell remains for a color, a row or a column, place the queen without hesitation.
Beginner mistakes
Forgetting the diagonal
The most common error: thinking of contact only in rows and columns. Yet the four corners count too. A queen truly forbids all eight neighbors, not four.
Confusing it with chess
Here, a queen does not attack its whole row, column and diagonals from afar. Only immediate contact matters for the neighbor rule. The reach constraint is limited to unique regions, rows and columns.
Guessing instead of deducing
Every grid has a single solution reachable by logic. Placing a queen on a hunch quickly leads to a contradiction. If you are stuck, look for the next strong constraint rather than betting.
Controls and grid sizes
You play with a finger or a mouse. Tap an empty cell to place a queen there. Tap it again to turn it into a mark, a cross that notes a forbidden cell and helps you picture the remaining candidates. A final tap clears the cell and resets it. Marks only serve your reasoning, they never affect how the grid is validated.
The rules stay identical whatever the size. A 6x6 grid needs six queens, a 7x7 needs seven, and so on up to the 9x9. The larger the grid, the more twisted the regions can get, and the longer the deduction runs. Start with the small formats to lock in the reflexes, then move up in size once the forced cell jumps out at you effortlessly. That is the best path toward the tougher grids.
Frequently asked questions
Can two queens be on the same diagonal far apart?
Yes. Unlike chess, queens in this game only conflict when they touch. Two queens on the same long diagonal are fine as long as they are not on adjacent, corner-touching cells.
How many queens go on the grid?
Exactly as many as the grid is wide: an 8x8 grid takes eight queens, one per row, one per column and one per colored region.
Is there always a single solution?
Yes. Every grid we generate is checked by a solver and kept only if it has exactly one solution, so the puzzle is always solvable by logic without guessing.
What do the X marks mean?
Marks are your notes. Tapping a cell twice marks it as a spot where a queen cannot go, which helps you see the remaining candidates. They do not affect the solution, they only support your reasoning.