Strategy · step 4 of 5

The color squeeze

Ask of a square: if a cat sat here, would some other region have anywhere left to live? If the answer is no, the square is a cross — today, with certainty.

Pink is down to two squares. Any cat on a highlighted square would touch both at once — suffocating pink. All four are crosses.

A cat eliminates its row, its column, and its eight neighbors. Usually that shadow falls on many colors and proves nothing. But when a region is down to its last few squares, the shadow can cover all of them — and a move that leaves any region homeless can never be part of the solution.

In the example, the pink region survives only in two adjacent squares. A cat placed diagonally above or below that pair touches both pink squares simultaneously. Pink would be extinct — so those squares were never legal in the first place.

Where squeezes hide

• Two-square regions are squeeze magnets. Adjacent pairs die to one diagonal neighbor; pairs in one line also die to anything else in that line (that half is really confinement — the two techniques overlap and that is fine).
• L-shaped and square-shaped triples have a center of gravity: squares adjacent to all three remaining cells kill the region just the same.
• Run the check when a region drops to ≤3 squares — scan the handful of squares whose shadow could plausibly cover all of them. It is a five-second check that unlocks boards which look completely stalled.

When MeowSolver shows a “color squeeze” hint, it names the square and the region it would suffocate — the two things you need to verify the logic yourself.

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