How to play Queens

Play Queens

The rules

The grid is split into regions, exactly as many as there are rows. Place queens so that:

• every row has exactly one queen;
• every column has exactly one queen;
• every region has exactly one queen;
• two queens never touch, not even diagonally.

Regions are shown both by color and by thick borders, so you can tell them apart without relying on color.

Every puzzle has exactly one solution, and you can reach it by logic alone, without guessing.

How to play here

• Click a cell to cycle between empty, an X mark and a queen. X is a note for yourself: “no queen here”.
• Keyboard: arrows to move, Q or 2 for a queen, X or 1 to mark, Space to cycle, Delete to erase.
• Queens in conflict are marked with diagonal stripes.

Difficulty levels

Techniques

Last cell

A row, column or region with only one free cell left. Its queen must go there. After placing a queen, mark X on its whole row, column and region, and on the eight cells around it.

Confinement

If all the free cells of a region lie on the same row, that row’s queen will be inside the region. So you can mark X on every other cell of the row. It works the other way too: if all the free cells of a row lie in one region, mark X on the rest of that region.

Shared attack

Look at a region with two or three free cells. Check which cells each possible queen would attack. A cell that all of them attack can’t hold a queen, whichever one turns out to be right.

Blocking attack

Test a free cell: if you put a queen there, would it block every free cell of another region (or row, or column)? If so, no queen can go there.

Tips

1. Start with the small regions. They have the fewest options.
2. Look for regions that lie entirely within one row or two neighboring columns.
3. Mark X generously. Most of the solving is knowing where the queens are not.