Queens

A logic puzzle game where you place queens on a colored grid

Each puzzle has exactly one solution. Easy through Expert puzzles are solvable through pure logic. Master puzzles require hypothesis testing — guess a placement and follow the logic until it confirms or contradicts.

Download on the App Store

Basic Rules

1

Place exactly one queen in each row

2

Place exactly one queen in each column

3

Place exactly one queen in each colored region

4

Queens cannot touch each other, not even diagonally (like kings in chess)

A B C D 1 2 3 4 ♛ ♛ ♛ ♛

A solved 4×4 puzzle

Controls

tap
Tap a cell Cycle through: empty → blocked → queen → empty
hold
Long press Mark cell as blocked (shows a dot)
drag
Drag across cells Mark multiple cells as blocked quickly

Solving Techniques

Every puzzle can be solved using these five techniques, from easiest to hardest:

1

Naked Single

Easy

When a region, row, or column has only one valid cell remaining, place a queen there. In the diagram, the yellow region only has one available cell left after eliminations — highlighted in red.

A B C D 1 2 3 4
2

Hidden Single

Medium

A cell must have the queen because placing it elsewhere would block a row or column. In the diagram, the yellow region has two candidates. The dashed cell would block row 1, so the highlighted cell is required.

A B C D 1 2 3 4
3

Region Elimination

Medium

If placing a queen would block all cells in another region, eliminate that cell. In the diagram, placing at the highlighted cell (B2) would block all remaining cells in the red region, so it must be eliminated.

A B C D 1 2 3 4
4

Locked Sets

Hard

When N regions can only place queens in N rows/columns, those lines are "claimed". In the diagram, the blue and green regions can only use rows 4-5, so the red region's cell in row 4 (highlighted) can be eliminated.

A B C D E 1 2 3 4 5
5

Chain Reasoning

Expert

When direct logic fails, test a hypothesis: assume a placement and follow forced moves. If you reach a contradiction (empty region/row/column), the assumption was wrong and that cell can be eliminated.

A B C D 1 2 3 4

Tips & Strategy

Start with eliminations

After placing each queen, immediately mark all cells it attacks as blocked.

Focus on small regions

Regions with fewer cells are more constrained and easier to solve first.

Use dots liberally

Marking blocked cells reveals patterns and makes solutions clearer.

Check intersections

When a region only fits in certain rows, look for locked sets opportunities.

Don't guess (except Master)

Easy through Expert puzzles are fully solvable through logic. If stuck, use hints.

Difficulty Levels

Easy through Expert are solvable through pure logic:

Easy Basic elimination and naked singles only
Medium Hidden singles and region elimination
Hard Locked sets patterns needed
Expert Multiple advanced techniques combined
Master Requires guessing — test placements and follow logic until confirmed or contradicted

Larger boards (8×8+) are inherently more difficult due to increased complexity.