Cat Sudoku: Free Online Picture Sudoku With Cats

What is Cat Sudoku?

Cat Sudoku is sudoku with the numbers taken out and nine silly cats put in. The rules do not change at all: one of each cat in every row, every column and every outlined box. Only the faces are new, and they have opinions.

Pick a 4×4 board of four kittens for a two-minute warm-up, a 6×6 for a tea break, or the full 9×9 with all nine cats. Every puzzle is made fresh, has exactly one answer and never needs a guess.

The cats react while you play. They purr when you finish a row, glare when two of them land in the same line, and nod off if you think for too long. Fill the board and they throw a small party.

It's free and it runs in your browser on a phone or a computer, with nothing to download and no account. If you would rather see digits, one switch turns every cat back into a number.

How to play Cat Sudoku

1. 

   1Pick a size and a level

   Tap the puzzle button at the top left. Choose Kittens (4×4), Cats (6×6) or Clowder (9×9), pick a level and press the big gold Play button. Easy is the level that comes with hints.

2. 

   2Tap a square, then its cat

   Look for a square where only one cat can go. Here every cat except Inky already sits in the square's row, column or box, so tap the empty square and then tap Inky on the pad.

3. 

   3One of each cat in every row, column and box

   With Inky seated, look at the three groups that square belongs to. Each row, each column and each outlined box needs one of every cat.

4. 

   4Pencil in the maybes

   When a square could take two or three cats, switch Notes on and tap each one. Small cats appear in the square as a reminder, and they are rubbed out for you when one of them is seated nearby.

5. 

   5Stuck on Easy? Ask for a hint

   Easy puzzles carry two hints each. A hint seats one cat, lights up the row, column or box it used, and explains why in plain words.

6. 

   6Glaring cats mean a wrong seat

   Seat a cat where its twin can already see it and they glare at each other. Tap Undo or Clear to send it back. The Oops counter keeps score, but nothing ends the game.

7. 

   7Solve a daily and keep your streak

   Three daily puzzles arrive every day, one for each size, and solving any one keeps your streak going. Seat the last cat and the cats throw a party, with your time, slips and badges on the card.

The rules in full

1. Tap the puzzle button at the top left, choose a size (4×4, 6×6 or 9×9) and a level, then press Play.
2. The aim is the same as any sudoku: every row, every column and every outlined box must hold one of each cat, with no cat twice.
3. Tap an empty square, then tap a cat on the pad to seat it there. The cats dealt at the start are fixed and cannot be moved.
4. Or work the other way round: tap a cat on the pad first, then tap every square that cat belongs in. Tap the same cat again to put it down.
5. Turn Notes on to pencil small cats into a square while you work out which ones could sit there.
6. Clear empties the picked square. Undo takes back your last move and Redo puts it back, as many times as you like.
7. A glaring cat is in the wrong seat. The Oops counter at the top counts your wrong seats, but no number of them ends the game.
8. On Easy puzzles you get two hints. A hint seats one cat and tells you why it goes there. Medium and harder puzzles have no hints.
9. Seat the last cat and the puzzle is solved. Your time, your slips and any new badges appear on the win card.

Cat Sudoku tips and strategy

• Read the small number on each pad cat. It shows how many of that cat still need a seat, and a cat with one left is nearly a free move.
• Scan one cat at a time. Pick Biscuit, say, and go box by box looking for the only square he could still sit in.
• When a row, column or box has a single gap, count who is missing. It is the quickest move on the board.
• Tap a seated cat to light up every copy of it. The rows and columns they cover show where the next one must go.
• Keep notes for squares with two or three possible cats. A board full of notes is harder to read than an empty one.
• Two squares in a box that can only hold the same two cats make a pair. Neither cat can sit anywhere else in that box.
• New to sudoku? Play a few 4×4 Kittens boards first. The thinking is the same and each one takes a minute or two.
• If the cats blur together on a small screen, turn on Number tags or Colour-blind friendly cats in Settings.

What is Cat Sudoku?

Cat Sudoku is a picture sudoku: the classic number-placing puzzle, played with nine cat faces where the digits 1 to 9 would be. Sudoku never used its numbers for sums, only as nine different symbols, so swapping them for cats changes nothing about the logic.

What it does change is how the puzzle feels. Instead of asking where the 7 goes, you are asking where Noodle goes, and Noodle looks pleased when you get it right.

Meet the nine cats

The cats are drawn to be told apart at a glance, even in a small square on a phone. Each has its own colour, its own markings and its own expression: Biscuit the orange tabby, Inky the black cat with yellow eyes, Mochi the cream loaf with her eyes shut, Pebble the grumpy blue critic and Domino in his dinner jacket.

On the bigger boards they are joined by Pickle, who is green and has forgotten that his tongue is out, Noodle the thinker, Plum the purple charmer with a wink, and Duchess, who is pink, crowned and in charge.

A 4×4 board uses the first four cats, a 6×6 the first six and a 9×9 all nine. Meet the cats in the menu has a short, not very flattering profile of each.

Three board sizes: 4×4, 6×6 and 9×9 cat sudoku

Kittens is a 4×4 board with four cats and boxes of 2×2. It takes a minute or two and is the gentlest way to learn how sudoku works, for a child or for anyone who has never tried one.

Cats is a 6×6 board with six cats and boxes two squares tall and three wide. It is long enough to need real thought and short enough for a tea break.

Clowder is the full 9×9 with all nine cats and 3×3 boxes, the same size as a newspaper sudoku. A clowder, by the way, is the proper word for a group of cats.

Difficulty levels graded by solving technique

Levels are set by the hardest step a puzzle needs, not by how empty it looks. Easy boards can be finished by finding the only seat left for a cat in a row, column or box. Medium adds squares where only one cat remains once you rule out all the others.

On the 6×6 and 9×9 boards, Hard asks for pairs and triples, and for noticing when a cat's place in one box rules it out along a whole line. The 9×9 board has a fourth level, Expert, which needs patterns that run across several rows and columns at once. On the 4×4 board the levels differ mostly by how few cats you start with.

Whatever the level, logic alone always solves the puzzle. You never have to guess.

Daily Cat Sudoku and your streak

Every day brings three new daily puzzles, one at each size. The week has a shape: gentle on Mondays, trickier by Saturday, and the hardest of the week on Sunday.

Solving any one of the three keeps your streak going, so a busy day only costs you a minute with the kittens. A strip of seven paws shows your week, and badges mark streaks of three, seven and thirty days.

A solved daily can be played again just for fun. Your first time stays as it was.

Hints, notes and mistake spotting

Hints follow one rule: two per puzzle on Easy, none on any other level. A hint seats a single cat and explains the reason, and it will never place the last cat for you. Undoing or starting the puzzle over does not hand the hints back.

Notes let you pencil small cats into a square, and Tidy my notes rubs them out as cats are seated nearby.

Spot mistakes as I play is on to begin with, so a wrong cat glares straight away. Switch it off in Settings for a stricter game in which only doubled-up cats are marked and you find the other slips yourself.

Colour-blind friendly cats, number tags and plain digits

The cats differ in more than colour: ears, markings, eyes and mouths are all different. Three switches in Settings help further.

Number tags put a small digit on every cat. Colour-blind friendly cats swaps the fur for a set of colours chosen to stay distinct with the common kinds of colour blindness, and turns the tags on as well.

Numbers instead of cats replaces every face with a plain digit, which makes the game a clean ordinary sudoku. Your puzzle carries on where it was.

Playing on a phone, a tablet or a keyboard

Cat Sudoku runs in the browser with nothing to install. On a phone the board takes the width of the screen with the cat pad underneath, and every button is big enough for a thumb.

On a computer you can play with the mouse or entirely from the keyboard: arrow keys to move, 1 to 9 to seat a cat, N for notes, Backspace to clear, Z and Y for undo and redo, H for a hint on Easy and P to pause.

Your puzzle is saved as you go, so it will be waiting if you close the tab.

Cat Sudoku FAQ