About PlayMiniSudoku

Apart from a handful of early launch boards, every puzzle here comes from our own generator rather than being set by hand, and all 900 pass the same checks.

1. 1

   Fill a complete grid

   A randomised backtracking solver fills an empty 6×6, 8×8 or 10×10 grid so that every row, column and box holds each digit once. That finished grid is the answer.

2. 2

   Take clues away, one at a time

   Cells are emptied in a random order. After each one, a solver counts the solutions (it stops at two). If emptying a cell would allow a second solution, the digit goes straight back. That is why every board has exactly one answer.

3. 3

   Grade it by the logic it needs

   A second solver works the board using only naked singles, then hidden singles. If naked singles alone finish it, it is easy. If it also needs hidden singles, it is medium. If singles run out before the end, it is hard. Clues keep coming out until the board lands in the target clue range for its size and grade.

4. 4

   Check the whole library again

   We re-ran the solution count and the grader over all 900 library puzzles. Every one has exactly one solution, and every grade matches the label you see on the board.

The how-to-play guide explains what each difficulty feels like in play, and the techniques page covers the moves the hard boards ask for.

Mini Sudoku is the same logic as classic 9×9 Sudoku in a smaller grid: every row, column, and region holds each digit exactly once. The 6×6 board, the size LinkedIn's Mini Sudoku uses, has the digits 1–6 in 2×3 regions and solves in a few focused minutes. Read more in what Mini Sudoku is.

• •A new daily 6×6 Mini Sudoku, the same board for everyone, and a streak that tracks your habit
• •Unlimited 6×6 practice drawing on all 300 boards of that size, with no repeats in a session
• •A library of 900 boards, 300 each at 6×6, 8×8, 10×10, easy to hard
• •Nine free printable PDF packs with answer keys
• •Pencil marks, Undo, three hints per puzzle, and instant error highlighting
• •Personal-best times for each grid size, saved in your browser
• •Free, with no sign-up and no email

Found a puzzle that looks wrong, a bug, or something you would like added? Use the feedback button in the menu bar, the contact page, or email playqueensgame@gmail.com.