Puzzle gm-5-0009

5 × 5 intro

Take this puzzle one clear step at a time.

Try the puzzle yourself, then explore how the deductions build.

Puzzle board · starting state

gm-5-0009: 5×5 regional boardBBBAABBBCADDCCCDDDCCEEEEC

Your starting point

This original 5×5 board has 5 connected regions and 2 fixed cats. The smallest region is A, with 3 cells. Start by ruling out every other cell in each fixed cat’s row, column and region, plus its immediate neighbors.

The verified route below uses 3 forced placements and 0 candidate-elimination steps after the givens. Region sizes: A: 3 · B: 6 · C: 7 · D: 5 · E: 4. These are observations about this board, not a guarantee that a smaller region always contains the next move.

Read each diagram in sequence. Cats and × marks in the before-state come from earlier deductions. Green outlines identify the current observation. Open the final answer only when you want the spoiler.

Step-by-step walkthrough

1Check row 2

row 2 has only one remaining candidate: row 2, column 2. Every other cell is excluded by earlier placements or deductions. Place the cat here.

gm-5-0009: 5×5 regional boardB×BBA×AB×BB×C×A×D×D×C×CC×DD×D×C×C×E×E×EE×C×Before step 1. Place one cat, then exclude 2 other cells.

2Check row 1

row 1 has only one remaining candidate: row 1, column 5. Every other cell is excluded by earlier placements or deductions. Place the cat here.

gm-5-0009: 5×5 regional boardB×B×B×A×AB×BB×C×A×D×D×C×CC×DD×D×C×C×E×E×EE×C×Before step 2. Place one cat, then exclude 0 other cells.

3Check row 5

row 5 has only one remaining candidate: row 5, column 3. Every other cell is excluded by earlier placements or deductions. Place the cat here.

gm-5-0009: 5×5 regional boardB×B×B×A×AB×BB×C×A×D×D×C×CC×DD×D×C×C×E×E×EE×C×Before step 3. Place one cat, then exclude 0 other cells.
Show solution · reveals all cat positions

The final cats satisfy every row, column and region quota, with no edge or corner contact.

gm-5-0009: 5×5 regional boardBBBAABBBCADDCCCDDDCCEEEEC

Cat positions: r1c5, r2c2, r3c4, r4c1, r5c3.

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How this puzzle and its reasoning are verified