Knowing the Catdoku rules is one thing; noticing which square they force is another. This walkthrough shows the reasoning on an original 5×5 example. You can copy the board onto paper and stop before each step to find the next cat yourself.
Find a row, column, or region with only one possible square. Place its cat, eliminate conflicts, and inspect the board again. Every placement below follows from that process.
Need the basics first? The Catdoku rules and solving guide explains the four constraints. Here, each row, column, and colored region needs exactly one cat, and cats cannot touch—even at a corner.
The teaching board
This is a puzzle made for this article, not a numbered level from the game. Its five regions are labelled A–E as well as colored, so you do not need to distinguish the colors. Each region is one connected area.
| Row / col | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|
| 1 | C | A | B | B | B |
| 2 | C | B | B | B | D |
| 3 | C | C | C | D | D |
| 4 | E | E | C | D | D |
| 5 | E | E | E | E | E |
For a text-only copy, the region letters in rows 1–5 are CABBB / CBBBD / CCCDD / EECDD / EEEEE. The single-square A region gives this beginner example a clear starting point.
1. Put the first cat in region A
Region A contains only R1C2. Every region needs a cat, so that square is forced.
Row 1 and column 2 now have their cats. Every other square in that row or column is unavailable. The cat also touches R2C1 and R2C3 diagonally, so those two squares are out.
2. Region B has only one square left
B covers three squares in row 1 and three in row 2. Its row-1 squares cannot contain another cat. That leaves R2C2, R2C3, and R2C4.
- R2C2 is in the occupied column 2.
- R2C3 touches the first cat diagonally.
- R2C4 has neither conflict. It is B’s only possible square.
Place the second cat at R2C4. Notice that “this square looks safe” was not the reason: every other B square was eliminated.
| Row / col | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|
| 1 | C | Acat | B | B | B |
| 2 | C | B | B | Bcat | D |
| 3 | C | C | C | D | D |
| 4 | E | E | C | D | D |
| 5 | E | E | E | E | E |
3. Inspect all of row 3
You do not need to finish regions alphabetically. Row 3 is now more useful than region C as a whole:
| Square | Can it contain the next cat? |
|---|---|
| R3C1 | Yes. Its row, column, and C region are unused, and it touches neither cat. |
| R3C2 | No. Column 2 already contains the first cat. |
| R3C3 | No. It touches the cat at R2C4 diagonally. |
| R3C4 | No. Column 4 already contains the second cat. |
| R3C5 | No. It also touches the cat at R2C4 diagonally. |
Only R3C1 remains. Place the third cat there. Region C is now complete too, so its other squares—including R4C3—cannot hold a cat.
4. Return to region D
D contains R2C5, R3C4, R3C5, R4C4, and R4C5.
Rows 2 and 3 already have cats, which removes D’s first three squares. Of the two left in row 4, R4C4 is in occupied column 4. D must therefore place its cat at R4C5.
5. Use the last unused column
The cats so far occupy columns 2, 4, 1, and 5. Row 5 still needs its cat, and column 3 is the only unused column. Place the last cat at R5C3, in region E.
This cat does not touch R4C5: their columns are two apart. The final placement satisfies the no-touch rule as well as finishing its row, column, and region.
Check the completed board
Show the solved board and all five coordinates
| Row / col | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|
| 1 | C | Acat | B | B | B |
| 2 | C | B | B | Bcat | D |
| 3 | Ccat | C | C | D | D |
| 4 | E | E | C | D | Dcat |
| 5 | E | E | Ecat | E | E |
The cats in neighboring rows have column gaps of 2, 3, 4, and 2, so none touch diagonally. Cats farther apart along a diagonal are allowed: the rule forbids touching, not sharing a whole chess-style diagonal.
This example has exactly one solution. More importantly for solving it yourself, each step above leaves exactly one candidate in the stated row or region; none depends on trying a cat and hoping the rest works.
Switch between rows, columns, and regions. A region that looks ambiguous may become obvious after you inspect a neighboring row. After every cat, check its diagonals before deciding where to look next.