Find the Cat #221: 10x10 Grid Puzzle (Hard)

hard

Tap a square: ✕ (ruled out) → 🐱 (cat) → clear

0 / 10 cats · 0:00
Red (6)Orange (17)Yellow (18)Green (3)Teal (9)Blue (1)Purple (14)Pink (10)Brown (15)Grey (7)

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.

  1. The Blue region has only one open square left: R10C5. Put a cat there.
  2. The Grey region has only one open square left: R8C4. Put a cat there.
  3. Wherever the cat in the Red region ends up, it rules out R2C7. Cross that square out.
  4. Wherever the cat in the Green region ends up, it rules out R1C8 and R2C10. Cross those squares out.
  5. Wherever the cat in the Pink region ends up, it rules out R9C7, R9C8, R9C9 and R9C10. Cross those squares out.
  6. Wherever the cat in the Orange region ends up, it rules out R6C7. Cross that square out.
  7. The Red and Green regions can only use rows 1 and 2, so rows 1 and 2 are already spoken for. Cross out R1C1, R1C2, R1C3, R2C1, R2C2, R2C3 and 1 more.
  8. The Teal region has only one open square left: R3C2. Put a cat there.
  9. The Pink region has only one open square left: R9C1. Put a cat there.
  10. The Yellow region has only one open square left: R5C3. Put a cat there.
  11. Wherever the cat in the Orange region ends up, it rules out R1C6, R2C6, R4C6 and R7C7. Cross those squares out.
  12. The Red region has only one open square left: R1C7. Put a cat there.
  13. The Green region has only one open square left: R2C9. Put a cat there.
  14. Wherever the cat in the Brown region ends up, it rules out R4C8 and R6C10. Cross those squares out.
  15. Row 4 has only one open square left: R4C10. Put a cat there.
  16. The Purple region has only one open square left: R7C8. Put a cat there.
  17. The Orange region has only one open square left: R6C6. Put a cat there.

About this puzzle

Where to start: the Blue region is a single square, so its cat is already decided. Its 10 color regions range from 1 square (Blue) to 18 squares. It can be solved in 17 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.

Every puzzle on this site has exactly one solution that can be reached by pure deduction. If you find yourself guessing, look again for a region or line with only a few open squares left.

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