GridMew1Check region A
region A has only one remaining candidate: row 1, column 8. 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.A corner singleton starts an upper-to-lower staircase
Original puzzle gm-8-0054
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 is only r1c8. Together with the r7c3 given, it reduces B to r2c4, then C to r3c7. Repeated regional singles carry the solve downward without requiring a candidate lock.
8×8 · 1 fixed cats · 7 explained deductions. Region sizes: A: 1 · B: 3 · C: 7 · D: 12 · E: 17 · F: 14 · G: 5 · H: 5.
A deduction worth checking
D next forces r4c5. Its neighborhood removes r5c6, helping the column-2 single appear in row 5.
A move to double-check · r5c6
r5c6 cannot be retained after r4c5. Their immediate corner contact applies even though the cells sit in different regions.
Green marks the cell being discussed, not a cat to place. This is the position before step 4; 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.
E E B B D C C A E E E B D C C C E E E D D D C C E E E D D D D D E E E E F F D D E H E G F F F F H H G G F F F F H H G G F F F F
Fixed cats: row 7, column 3. One cat is required in each row, column and region.
Step-by-step walkthrough
2Check 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 2. Place one cat, then exclude 8 other cells.3Check region C
region C has only one remaining candidate: row 3, column 7. 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 D
region D has only one remaining candidate: row 4, column 5. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 4. Place one cat, then exclude 6 other cells.5Check column 2
column 2 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 5. Place one cat, then exclude 2 other cells.6Check row 6
row 6 has only one remaining candidate: row 6, column 6. 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 8
row 8 has only one remaining candidate: row 8, column 1. 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: r1c8, r2c4, r3c7, r4c5, r5c2, r6c6, r7c3, r8c1.
Try another puzzle
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