Find the Cat #176: 8x8 Grid Puzzle (Medium)
mediumTap a square: ✕ (ruled out) → 🐱 (cat) → clear
A 8x8 logic grid, 8 colors, 8 cats. Work out where each cat sits using nothing but the rules -- there is only one correct layout and no guessing is needed.
- One cat in every row and every column.
- One cat in every color region.
- Cats can’t touch — not even diagonally.
Step-by-step solution
Squares are written as R<row>C<column>, counting from the top-left. Cross out the squares listed, and place a cat wherever a step says so.
- The Green region has only one open square left: R8C6. Put a cat there.
- Wherever the cat in the Red region ends up, it rules out R6C5. Cross that square out.
- Wherever the cat in the Orange region ends up, it rules out R2C2. Cross that square out.
- Wherever the cat in the Blue region ends up, it rules out R1C3. Cross that square out.
- Wherever the cat in the Pink region ends up, it rules out R1C7 and R3C8. Cross those squares out.
- Wherever the cat in the Blue region ends up, it rules out R2C5. Cross that square out.
- Wherever the cat in row 3 ends up, it rules out R4C2. Cross that square out.
- The Blue and Pink regions can only use rows 1 and 2, so rows 1 and 2 are already spoken for. Cross out R1C1, R1C2 and R2C1.
- The Orange region has only one open square left: R3C1. Put a cat there.
- Wherever the cat in the Yellow region ends up, it rules out R6C3. Cross that square out.
- Wherever the cat in the Teal region ends up, it rules out R4C7, R4C8, R5C4 and R5C5. Cross those squares out.
- Wherever the cat in the Red region ends up, it rules out R7C3. Cross that square out.
- Wherever the cat in column 2 ends up, it rules out R5C3. Cross that square out.
- The Purple and Pink regions can only use columns 7 and 8, so columns 7 and 8 are already spoken for. Cross out R5C7.
- Wherever the cat in the Teal region ends up, it rules out R4C3. Cross that square out.
- Column 3 has only one open square left: R2C3. Put a cat there.
- The Pink region has only one open square left: R1C8. Put a cat there.
- The Purple region has only one open square left: R6C7. Put a cat there.
- The Red region has only one open square left: R7C4. Put a cat there.
- The Yellow region has only one open square left: R5C2. Put a cat there.
- The Teal region has only one open square left: R4C5. Put a cat there.
About this puzzle
Where to start: the Green region is a single square, so its cat is already decided. Its 8 color regions range from 1 square (Green) to 15 squares. It can be solved in 21 deduction steps using grouped row/column/region deductions.
Start with the region that is a single square -- its cat has nowhere else to go. Cross out that cat's whole row, column and neighbors, then move on to the next-smallest regions: with only a couple of squares each, they leave very little room.
Stuck? Open the step-by-step solution below -- each step names the row, column or color involved, so you can use it as a hint and then finish the puzzle yourself.