GridMew1Check region A
region A has only one remaining candidate: row 1, column 1. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 1. Place one cat, then exclude 13 other cells.Two singleton regions steer a seven-placement finish
Original puzzle gm-8-0030
By GridMew · Published 15 October 2026 · Updated 16 October 2026
8 × 8 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.
A at r1c1 and D at r4c8 are both single-cell regions. Alongside the bottom-row given, they establish long exclusions across the board. Region G becomes the next place to inspect.
8×8 · 1 fixed cats · 7 explained deductions. Region sizes: A: 1 · B: 7 · C: 14 · D: 1 · E: 15 · F: 19 · G: 4 · H: 3.
A deduction worth checking
G resolves at r7c5. Its corner effects remove r6c4 and r6c6, while the column effect reaches the upper rows.
A move to double-check · r6c6
r6c6 touches the new G cat at r7c5. Leaving it available would hide why the later column-7 single can be found.
Green marks the cell being discussed, not a cat to place. This is the position before step 3; 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.
A B B B B C C C E E B B B C C C E E E C C C C C E E E C C C F D E E E F F F F F E E F F F F F F E E F G G F F F H H H G G F F F
Fixed cats: row 8, column 3. One cat is required in each row, column and region.
Step-by-step walkthrough
2Check region D
region D has only one remaining candidate: row 4, column 8. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 2. Place one cat, then exclude 12 other cells.3Check region G
region G has only one remaining candidate: row 7, column 5. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 3. Place one cat, then exclude 8 other cells.4Check region B
region B has only one remaining candidate: row 2, column 4. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 4. Place one cat, then exclude 4 other cells.5Check column 7
column 7 has only one remaining candidate: row 6, column 7. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 5. Place one cat, then exclude 2 other cells.6Check row 5
row 5 has only one remaining candidate: row 5, column 2. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 6. Place one cat, then exclude 1 other cells.7Check row 3
row 3 has only one remaining candidate: row 3, column 6. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 7. 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: r1c1, r2c4, r3c6, r4c8, r5c2, r6c7, r7c5, r8c3.
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