Meowdoku Tips and Strategy: Solving Cat Sudoku Boards

Meowdoku tips are really about one habit: never place a cat you cannot justify. Every board is built with a single solution and checked before it ships, so a guess is always a sign that a deduction is still sitting somewhere on the grid, waiting to be seen.

The techniques below run from the ones that crack a board open to the ones that rescue it once the obvious moves are gone. They all come out of the puzzle's four conditions, so none of them asks you to memorise anything.

Read them once, then play a few intro boards with one tip in mind at a time. A technique sticks faster when you are hunting for a single thing rather than trying to hold all of them at once.

The most reliable first move is a cell that has no rival. Look along a row, a column or a coloured region and count how many cells could still legally take a cat. When the answer is one, the cat goes there.

Small regions produce these single-option cells quickly, which is why the tightest part of the grid is usually the right place to look first. A region of two cells, or a region trapped in a corner, often collapses in a single step and hands you a placement the rest of the board was waiting on.

This is also the test for whether you need a fancier technique at all. If any row, column or region still has exactly one open cell, you have a free move and no reason to think harder.

An X mark is your memory. Every time a placement rules a cell out, mark it, so that the deduction is visible instead of something you have to keep re-deriving. On a 9×9 board the same cell gets eliminated several times, and tracking that in your head is where most stalls begin. A single X costs nothing and saves a re-scan later. Across a full board, those saved re-scans are the difference between a steady solve and a grind.

The marks pay off twice. They stop you from re-checking cells you have already dismissed, and they make a single-option cell obvious: when a region or a line is mostly X marks with one clean cell left, the cat belongs in that cell.

Beginners who skip the marks tend to re-scan the same regions in circles. It feels faster to keep clicking than to note things down, but the note is what ends the loop.

The no-touching rule is the strongest tool in the game, and it is the one that separates a fast solve from a slow one. A single cat rules out its whole row, its whole column, its own region, and eight cells around it. Those restrictions overlap, and the overlap is where forced moves appear.

Watch what happens to a region that touches a cat you just placed. Some of its cells fall to the row rule, some to the column rule, and the diagonal cells fall to adjacency. Whatever remains is that region's real candidate list, and it is often much shorter than it looked a moment ago.

This is why the order of your placements matters. A cat placed early on a lonely region can look harmless and still erase the only legal cell of a region two steps away, so it is worth scanning for those collateral effects before you commit.

When the easy singles dry up, stop looking at individual cells and count regions instead. For each coloured area, ask how many of its cells are still allowed by its row, its column and the adjacency rule. Regions that have thinned down to two candidates usually partner with another region and surrender a placement.

The counting is quickest on the awkward regions: long thin ones, or ones wrapped around a corner where the diagonal rule bites hardest. A region that keeps its options because it is wide and central can usually wait until its neighbours have decided things for it.

If a region still refuses to narrow, look at the row and column it sits in. A region is only as constrained as the lines crossing it, and one placed cat along either line can cut its candidate list in half.

The Check button is a safety net rather than a hint. It reports the first problem it finds, such as a row holding two cats or a pair of cats in contact, and it leaves the solving to you. Used after a batch of placements it catches a slipped cat before the error buries itself under later moves.

Each level also carries a short written hint, shown in the How to play dialog, and it is pitched at the board in front of you rather than at the puzzle in general. On an intro board the hint nudges you toward marking cells with X; on a hard board it points at the single-option lines and regions.

Take the hint when you have already scanned and found nothing, not when the board merely looks busy. The gap between those two moments is where the learning happens, and spending it on a scan rather than on a reveal is what makes the next board easier.