One cat. Three kinds of space.

The board in front of you

A board is a square grid — 4×4 at its smallest, 12×12 at its largest — divided into connected colored regions. The number of regions always equals the width of the grid, so an 8×8 board has eight rows, eight columns, eight regions, and exactly eight cats. Those same eight placements satisfy all three families of constraint at once.

That overlap is the entire game. A cat never answers one question at a time. Place one and you have resolved a row, a column, and a region together, while ruling out the eight cells that surround it. Beginners hunt for where a cat goes. Stronger players prove where it cannot.

Read the board in layers

1. Scan rows and columns. If every cell but one is ruled out, the remaining cell must hold a cat. This is the move you will make most often, and it is worth re-scanning every line after each placement.
2. Scan each color. Every connected region needs exactly one cat, however it bends across rows or wraps around its neighbors. Small regions are the most generous: a two-cell region is already half solved.
3. Follow the automatic paws. Placing a cat rules out its row, its column, its region, and every adjacent cell. The board marks these for you, but tracing them by eye is the habit that makes hard puzzles readable.

Your two tools

1. The paw marks a cell as impossible. Use it constantly. A paw is not a guess — it is a proof that no cat can live there, and it is how the next certain move becomes visible.
2. The cat marks a placement. Reach for it only when a cell is forced. If you are asking yourself whether a cat belongs somewhere, what you actually need is a paw somewhere else first.
3. On touch screens, long-press places a cat. Tap to mark, long-press to place. This keeps your thumb in one mode while you sweep through eliminations.

A worked opening

Start with the smallest region on the board. Suppose it spans only two cells, and both sit in row 4. You cannot yet say which of the two holds the cat — but you already know that row 4’s cat is one of them, and therefore that every other cell in row 4 is impossible. Mark them all with paws.

That single deduction usually cascades. A column that just lost three candidates may now have one cell left. Place its cat, sweep its neighbors, and re-read the regions it touched. Most boards unravel exactly this way: not from a brilliant placement, but from one small region forcing a line, which forces a cell, which forces the next.

Use marks, not guesses

Mark cells with the paw tool as you eliminate them. Switch to the cat tool only when a placement is certain. Every generated puzzle on this site can be solved through an unbroken chain of certain moves — so if you are guessing, there is a deduction still sitting on the board that you have not found yet.

This matters more than it sounds. A guess that happens to be right leaves you holding a position you cannot explain, and the next contradiction sends you back with nothing to trust. A board solved by elimination stays solved.

What a hint actually gives you

A hint never reveals a random cat. It finds the next move that is logically certain from your current position and names the rule that forces it. If you take a hint and the reasoning surprises you, that technique is worth learning — it is almost always the one blocking the rest of the board.

When you get stuck

1. Re-sweep the last cat you placed. One missing paw beside a placed cat is the most common reason a perfectly solvable board looks dead.
2. Count the small regions. Regions of two or three cells constrain lines quickly, and they are easy to overlook once the rest of the board fills up.
3. Look for lines with two candidates. Two rows restricted to the same two columns reserve those columns for each other, which frees every other row that crosses them.
4. Take a hint and read the reason. The explanation names the technique, so a hint costs you one move and can hand you a pattern you will reuse for the rest of the board.