Find the Cat #186: 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 Purple region has only one open square left: R3C5. Put a cat there.
- Wherever the cat in the Red region ends up, it rules out R1C1, R1C2, R1C3, R1C4 and R2C7. Cross those squares out.
- The Pink region has only one open square left: R2C2. Put a cat there.
- The Orange region has only one open square left: R7C1. Put a cat there.
- The Teal region has only one open square left: R4C3. Put a cat there.
- The Blue region has only one open square left: R6C6. Put a cat there.
- The Yellow region has only one open square left: R8C4. Put a cat there.
- The Green region has only one open square left: R5C8. Put a cat there.
- The Red region has only one open square left: R1C7. Put a cat there.
About this puzzle
Where to start: the Purple region is a single square, so its cat is already decided. Its 8 color regions range from 1 square (Purple) to 16 squares. It can be solved in 9 deduction steps using "wherever it goes" eliminations.
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.
When you fill the last cat, press Check Answer -- the grid is verified against the stored solution and any broken rule is named so you know where to look.