Purrdoku: sudoku with cats

The rules of Purrdoku

• One of each cat in every row. A 9×9 board has nine different cats, numbered 1 to 9. Each row holds every one of them exactly once.
• One of each cat in every column. The same goes for every column.
• One of each cat in every box. The thicker lines mark the boxes: 2×2 boxes on the smallest boards, 2×3 on six-by-six boards and 3×3 on the classic grid.
• One answer. Every board has exactly one solution, checked by the site’s solver, so every piece can be found by reasoning.

Choose a square, then a cat from the palette above the board, or type its number. Notes mode lets you pencil in the cats a square could still hold. You can switch between cat pictures and plain numbers at any time. Small 4×4 and 6×6 practice boards use Easy; choose 9×9 for Medium and Hard.

From first steps to wings

Hints follow a ladder of techniques, and the Journey climbs the same ladder. Only piece that fits: every other cat is already in the square’s row, column or box. Only square left: a cat has just one place left in a row, column or box. Locked in a line: inside a box, a cat can only go in one row or column, so it can’t go anywhere else in that line. Pairs and triples: two squares that can only hold the same two cats keep those cats for themselves. X-Wing and Y-Wing: patterns across several lines that remove a candidate either way. Easy boards need only the first two steps; hard boards need wings.

Play your way

Journey has 120 numbered levels in twelve chapters, from small boards to the biggest ones, and the map lets you revisit any level. The daily challenge changes at midnight UTC: Mondays and Tuesdays are easy, Wednesday to Friday medium, and weekends hard. Free practice makes a new board in the size and difficulty you choose.

Every attempt has three Hints and one Assist. Hint explains a step you can prove from what is on the board. Assist makes that step for you. Corrections are free. Undo changes the board but never refunds spent help. Retry asks before starting again, and earlier clears stay earned. Your Purrdoku progress stays in this browser, separate from the other games, and solved boards count toward the shared cast cards.

Purrdoku questions