HomeDailyPuzzlesStrategiesOther GamesDiscord
Strategy Guide

Queens Puzzle Strategy: Techniques to Solve Every Board

Learn the deductions the hint system uses to solve every Queens puzzle, from forced moves you’ll spot in your first minute to test chains only the hardest boards require.

Start learningPlay a puzzle

In a hurry? The whole guide in five bullets.

  • • Place N queens on an N×N board, one per row, column, and region.
  • • Queens may not touch, not even diagonally.
  • • If a region has only one legal cell, a queen must go there (forced queen).
  • • If a region’s legal cells all share one row or column, that line is reserved for that region.
  • • When you’re stuck, ask “what if I placed a queen here?” and look for a region with no legal cells left.
Jump to a technique

How to Solve Queens Puzzles Step by Step

Every Queens solve follows the same loop. After each queen you place, the board automatically marks cells that conflict. That is the first and cheapest deduction. Then you scan the board in four passes, each one harder than the last.

  1. Forced queens: a region, row, or column with one legal cell.
  2. Line locks: a region whose cells all share one row or column.
  3. Region group locks: N regions that fit into exactly N rows or columns.
  4. Test a queen: ask “what if I placed a queen here?” and check whether another region has no legal cells left.

The sections below teach each pass in order. Beginners can stop after the Essential tier and solve 80% of 7×7 and 8×8 puzzles. The harder tiers explain the reasoning your in-game hints will show you on 10×10 boards and above.

Essential Techniques

These three cover roughly 80% of 7×7 and 8×8 puzzles. Master them first.

Forced Queen

Essential

When a region, row, or column has exactly one legal cell, a queen must go there.

How to spot it
Look at one region, row, or column at a time. Count the empty cells where a queen could still go. If there is only one legal cell left, you have found a forced move.
What to do
Place a queen in that single legal cell. Every other cell in its row, column, and region now becomes invalid, along with its four diagonal neighbors. Mark all of them.
Why it works
Every region, row, and column needs exactly one queen. If only one cell is available, that cell must be the queen.
When it applies
Every puzzle. This is the first deduction to look for after placing any queen or marking any cell.

Row/Column Elimination

Essential

When a queen is placed, every other cell in its row and column becomes invalid.

How to spot it
After placing any queen, scan its entire row and its entire column. Any empty cell along those lines can no longer hold a queen.
What to do
Mark an X on every empty cell that shares a row or column with a placed queen. Do the same for cells in the queen's region and for the four diagonally-adjacent cells.
Why it works
The rules allow one queen per row, one per column, and one per region. Queens also cannot touch diagonally. Any cell that would break one of those rules is unusable.
When it applies
Right after every queen placement. The game auto-marks most of these for you, but recognizing the pattern trains your eye to see where the remaining queens must go.

Region Line Lock

Essential

If a region's legal cells all sit in the same row or column, that line is reserved for that region.

How to spot it
Pick a region that does not yet have a queen. Look at the cells in that region where a queen could still go. If every legal cell is in the same row or the same column, the region is locked to that line.
What to do
Mark every cell in that row (or column) that belongs to a different region. Those cells can no longer hold a queen, because the line is already committed to the locked region.
Why it works
The locked region will place its queen somewhere in that row (or column). Since every row and column can only hold one queen, no other region can use the same line.
When it applies
Commonly on 8x8 and larger puzzles after a handful of queens are placed. The hint system shows these as messages like "The blue region must use row 3."

Intermediate Techniques

Two deductions that appear once queens have filled in the simpler rules, especially on 9x9 and 10x10 boards.

Diagonal Neighbor Elimination

Intermediate

When every possible queen for a region touches the same diagonal neighbor, that neighbor cannot hold a queen.

How to spot it
Pick a region with only two or three legal cells left. Look at the diagonal neighbors of each legal cell. If every option touches the same outside cell diagonally, that outside cell is blocked.
What to do
Mark the shared diagonal neighbor as invalid. No matter which legal cell the region uses, that outside cell would touch the queen diagonally.
Why it works
Queens cannot touch diagonally. If every possible queen in a region would touch the same outside cell, that outside cell cannot be a queen.
When it applies
Appears when a region has been narrowed to a few options. Recognizing it helps you mark cells that do not share a row, column, or region with an existing queen.

Region Group Lock

Intermediate

When N regions' legal cells fit in exactly N rows or columns, those lines are reserved for those regions.

How to spot it
Find a small group of regions without queens, often two or three. If all legal cells for those regions sit inside the same number of rows or columns, the group has locked those lines.
What to do
Mark every cell in those rows (or columns) that belongs to a region outside the group. No outside region can claim a queen in a line that is already spoken for.
Why it works
N regions need N different rows or columns for their queens. If only N lines are available to the group, the group uses all of them. No other region can use those lines.
When it applies
Common on harder 9x9 and 10x10 puzzles. This is the larger version of a Region Line Lock: one region can reserve one row, and two regions can reserve two rows.

Line Group Lock

Intermediate

When N rows or columns can only be filled by the same N regions, those regions are locked to those lines.

How to spot it
Pick a small set of empty rows or columns. Look only at legal cells in those lines and list their regions. If N lines can only use the same N regions, those regions must supply the queens for those lines.
What to do
Mark cells from those same regions outside the locked rows or columns. Since the regions are already needed inside the locked lines, they cannot place their queens anywhere else.
Why it works
The locked lines need N queens, and only the N listed regions can provide them. Those regions are used up by the lines, which rules out their legal cells elsewhere.
When it applies
Useful on puzzles where region locks are not enough, especially larger boards where several rows or columns have been narrowed to the same small set of regions.

Expert Techniques

You’ll mostly see these on 10x10+ puzzles. The hint system can compute them for you. Knowing the pattern explains why some positions fail even after every simpler rule has been applied.

Test a Queen

Expert

If placing a queen in a cell would leave some other region with no legal cells, that cell cannot hold a queen.

How to spot it
Pick a legal cell you are unsure about. Imagine placing a queen there and applying the marks that would follow. The queen's row, column, region, and diagonal neighbors all become invalid. Now check every region that still needs a queen.
What to do
If any region would have zero legal cells after the test, mark your original cell as invalid. If every region still has at least one legal cell, that test did not prove anything yet.
Why it works
A legal solution needs one queen in every region. If a test placement makes that impossible, the tested cell cannot be part of the solution.
When it applies
When the simpler techniques have stopped advancing the puzzle. Start with cells that affect many other cells, such as crowded middle cells or cells in tight regions.

Follow a Test Chain

Expert

Test a queen, then keep following the forced moves it creates before checking whether a region has no legal cells left.

How to spot it
You tested a cell and no region immediately ran out of legal cells, but the puzzle still will not move. That is a sign to follow the forced moves created by the test.
What to do
Mentally place the queen, apply the automatic marks, then work through every forced queen and group lock that the new position creates. Keep chaining deductions until you either stall out or find a region with no legal cells. If any region has no legal cells, the original placement was impossible.
Why it works
One tested queen can force another queen, which can force another. The contradiction may only appear after several forced moves.
When it applies
The hardest 10x10 and 11x11 puzzles. The hint system can do this reasoning for you, but learning the pattern explains why some cells look safe at first and still fail.

Quick Tips & Common Mistakes

  • • Mark before you place. Most deductions work on marked cells, not on queens.
  • • Use the X markers. Turn on markers so the game will auto-mark conflicts. It doubles your speed.
  • • Check diagonals last. Row, column, and region are easy to see; forgetting the diagonal rule is the #1 source of errors.
  • • When stuck, pick the tightest region. Start your test on whichever region has the fewest legal cells.
  • • Every region matters. If a technique eliminates a cell, always check whether any region is now reduced to a single legal cell.
  • • Hints teach. Use the hint button when stuck. It will show which technique applies and why.

Frequently Asked Questions

What is the best Queens puzzle strategy for beginners?

Start with forced queens: look for any region, row, or column that has exactly one legal cell. After that, scan for line locks, where a region's legal cells all share one row or column. Those two techniques alone solve most 7x7 and 8x8 puzzles.

How do I solve a Queens puzzle when I’m stuck?

Pick a region with only two or three legal cells. Test each cell one at a time and check whether any other region would have no legal cells left. If a test leaves a region with no legal cells, mark the tested cell as invalid.

Do I need math to get good at Queens?

No. Every deduction is a counting argument: “one queen per row/column/region” and “N regions need N rows.” Recognizing the patterns is what takes practice, not algebra.

Why can’t queens touch diagonally?

That is the extra rule that makes Queens distinct from the classical N-Queens problem and from Star Battle. It makes you think about adjacency alongside row, column, and region, which is what gives the puzzle its shape.

What does the hint button do?

The hint button applies the same deductions you learn on this page. It will either place a forced queen, mark a cell you should have already marked, or explain which technique proves a cell is impossible.

How are the techniques ranked by difficulty?

Essential (forced queens, row/column elimination, line locks) covers easy and medium puzzles. Intermediate (diagonal adjacency, group locks) shows up on 9x9 and 10x10 boards. Expert (testing a queen and following test chains) is only needed on the hardest puzzles.

Ready to apply what you learned?

Pick any of today’s puzzles and test these deductions live.

Play today’s puzzleBrowse all puzzles