Find the Cat #282: 10x10 Grid Puzzle (Hard)
hardTap a square: ✕ (ruled out) → 🐱 (cat) → clear
Find the 10 hidden cats. Each row, each column and each colored region holds exactly one, and cats never sit on neighboring squares, diagonals included.
- 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 Red region has only one open square left: R10C2. Put a cat there.
- The Yellow, Teal and Blue regions can only use rows 1, 2 and 3, so rows 1, 2 and 3 are already spoken for. Cross out R2C5, R2C6, R2C7, R3C1, R3C3, R3C4 and 3 more.
- The Green region has only one open square left: R4C3. Put a cat there.
- Wherever the cat in the Yellow region ends up, it rules out R5C1, R6C1, R7C1 and R8C1. Cross those squares out.
- The Orange region has only one open square left: R7C4. Put a cat there.
- The Brown region has only one open square left: R5C5. Put a cat there.
- Wherever the cat in the Purple region ends up, it rules out R6C7 and R6C8. Cross those squares out.
- The Pink region has only one open square left: R8C6. Put a cat there.
- Column 7 has only one open square left: R1C7. Put a cat there.
- The Yellow region has only one open square left: R2C1. Put a cat there.
- The Blue region has only one open square left: R3C10. Put a cat there.
- The Purple region has only one open square left: R6C9. Put a cat there.
- The Grey region has only one open square left: R9C8. Put a cat there.
About this puzzle
Where to start: the Red region is a single square, so its cat is already decided. Its 10 color regions range from 1 square (Red) to 16 squares. It can be solved in 13 deduction steps using grouped row/column/region deductions.
If a row and a color both have only two open squares and share them, those two lines are locked together -- neither can use squares anywhere else.
This is a variation of the Star Battle family of grid puzzles, sometimes also called Queens-style puzzles, with cats in place of stars.