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Queens

Place one queen in every row, column and lettered region, with no two touching — 5×5 up to 9×9, each with exactly one answer.

  • Logic
  • Untimed
  • 5 levels

How it plays

The board is split into regions, each marked by a letter in the corner of its cells. Put exactly one queen in every row, every column and every region, and no two queens next to each other, not even diagonally.

Mark a queen ♛ and every other cell ·. A queen rules out its row, its column, its region and its eight neighbours. A region that fits inside one row must hold that row's queen, so the rest of the row is empty.

Levels grow the board from 5×5 to 9×9. Every puzzle has exactly one answer, checked by trying every placement.

Keys

Space starts and skips ahead · 1–9 pick · Enter submits · Esc stops. On a phone, tap.

What it trains

This practises elimination and case-splitting on a board. It is practice at these puzzles, not a measured gain in reasoning elsewhere.

Learn

How to get better at queens: the method, the techniques, what each new level asks of you, and the traps the wrong answers are made of.

Your approach to each question

  1. Find the regions first: read the letters and note the smallest ones, and any that sit inside a single row or column.
  2. Place every queen that is forced — a one-cell region, or a given queen — and mark · on its row, its column, its region and, with touching banned, its eight neighbours.
  3. Look for regions squeezed into one line, then pairs of regions squeezed into two lines, and clear the rest of those lines.
  4. Check each row, column and region for one that has a single cell left. That cell is the queen; mark around it and go back to step 3.
  5. If nothing is forced, take the smallest region, try its first cell, and follow it until a row, column or region has no cell left — then that cell was wrong.

Techniques and tricks

  • A region in one line claims it

    If every cell of a region sits in one row, that row’s queen must be in the region. Every cell of the row outside the region is empty. The same holds for columns.

  • Two regions, two lines

    If two regions fit together inside the same two rows, those rows’ two queens belong to them. Every other cell in those two rows is empty. It works for three regions in three rows too, and for columns.

  • The other way round

    If a row’s open cells all lie in one region, that region’s queen is in the row, so every cell of the region outside that row is empty.

  • Cells every candidate touches

    With touching banned, find the cells that every possible queen of a region would touch. They are empty, whichever cell the queen takes.

    e.g. A region of two side-by-side cells in row 3, columns 2 and 3: either queen touches columns 2 and 3 of rows 2 and 4, so those four cells are empty.

  • One queen per two-by-two

    With touching banned, no 2×2 block can hold two queens. If a region’s cells all lie in one 2×2 block, the rest of that block is empty.

  • Try the smallest region

    When stuck, the region with the fewest open cells has the fewest cases. Try each cell in turn and keep the one that does not run a row, column or region out of space.

As the levels climb

  • The board grows by one each level: 5×5, 6×6, 7×7, 8×8, 9×9, up to the “Largest board” setting, and then the ladder stops.
  • Each size up adds a region, a row and a column to track. Work from the smallest region outwards, and reach for two-regions-in-two-lines as soon as single-line claims run out.
  • Now and then the regions alone allow two answers, and a queen is given to settle it. Start from it: clear its row, column, region and neighbours first.

Traps to avoid

  • The diagonal touch: two queens in neighbouring rows one column apart obey the row and column rules but touch at a corner. With “Queens may not touch” on, that breaks the puzzle.
  • Forgetting the region rule: a row and a column can both look clear while the region already has its queen. Mark the whole region · as soon as its queen is in.
  • Misreading a letter: regions are shown by the letter in each cell’s corner, not by colour. Before you place a queen, check which region the cell belongs to.
  • Clearing a line too soon: a region in one row claims that row, not its column. Only clear the column if the region also sits in one column.

How to practise

  • Set “Largest board” to 6 or 7 and play until you spot the squeezed regions in the first few seconds, then let it grow to 9.
  • Turn “Queens may not touch” off to practise the row, column and region moves alone; turn it back on to add the neighbour and 2×2 moves.
  • Mark the cells you rule out as · as you go — pressing 2 does it from the keyboard. Unmarked cells count as · when you submit, but marks show you what is left.
  • With “Time pressure” on, the clock gives a minute and a half plus four seconds for every open cell; keep it off until the openings are automatic.

Levels

It is untimed unless you turn the clock on. There are 5 levels with the default settings, and the counter stops at the real top. Your level is judged on your last ten answers, every ten: 90% moves you up, below 80% moves you down, which holds most people near four in five right.

All of it is in the settings beside Start — how many answers a judgement looks at and how often it recalibrates, the thresholds, the time, which questions, how many options, and whether you see each verdict at once or review them together at the judgement. You can also jump to any level.

More logic

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