GridMew1Check row 4
row 4 has only one remaining candidate: row 4, column 1. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 1. Place one cat, then exclude 4 other cells.Follow a forced cat up the left column
Original puzzle gm-5-0045
By GridMew · Published 15 October 2026 · Updated 16 October 2026
5 × 5 practice
Read the starting position, follow the deductions, and check the move that is easy to misread.
Puzzle board · starting state
How to approach this board
Coordinates such as r2c3 mean row 2, column 3. Count rows from the top and columns from the left.
The fixed cat at r5c3 fills E. Inspect row 4 after removing that region and the given’s neighbors: only the leftmost cell survives. Its effect is much wider than the neighboring square.
5×5 · 1 fixed cats · 4 explained deductions. Region sizes: A: 2 · B: 7 · C: 1 · D: 5 · E: 10.
A deduction worth checking
After row 2 resolves at r2c2, row 3 is forced at r3c5. That placement removes the remaining top-right column candidate.
A move to double-check · r1c1
r1c1 must be crossed out when r4c1 is placed. They do not touch, but they cannot both occupy column 1.
Green marks the cell being discussed, not a cat to place. This is the position before step 1; compare the deduction below.
Read the starting board as text
Each line is one row, left to right. Matching letters belong to the same connected region.
D B B A A D B B E E D B B E C D B E E E D E E E E
Fixed cats: row 5, column 3. One cat is required in each row, column and region.
Step-by-step walkthrough
2Check 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.
Before step 2. Place one cat, then exclude 1 other cells.3Check row 3
row 3 has only one remaining candidate: row 3, column 5. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 3. Place one cat, then exclude 1 other cells.4Check row 1
row 1 has only one remaining candidate: row 1, column 4. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 4. 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.
Cat positions: r1c4, r2c2, r3c5, r4c1, r5c3.
Try another puzzle
Clear the bottom row, then work upward
gm-5-0029 · 5×5 · practice
Practice single-candidate placements on another 5×5 board.
Read this walkthrough →A bottom-left singleton opens a distant column
gm-6-0009 · 6×6 · practice
Transfer single-candidate placements to a 6×6 grid; compare how the candidates change.
Read this walkthrough →Two possible cats, one shared exclusion
gm-5-0001 · 5×5 · challenge
Compare this route with shared-neighbor exclusions, and check why that different rule is needed.
Read this walkthrough →