GridMew1Check region B
region B 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 1. Place one cat, then exclude 9 other cells.A row lock can force a cat in the same row
Original puzzle gm-6-0012
By GridMew · Published 15 October 2026 · Updated 16 October 2026
6 × 6 challenge
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 bottom-left given reduces B to r2c2. After that placement, row 3’s surviving candidates all lie in C. Use that reservation before trying to choose among the three row-3 positions.
6×6 · 1 fixed cats · 7 explained deductions. Region sizes: A: 8 · B: 3 · C: 7 · D: 10 · E: 6 · F: 2.
A deduction worth checking
The C reservation removes other candidates from column 6, making r3c6 its only option. A later row-4 lock provides another column single.
A move to double-check · r5c3
At step 4, row 4’s cat must be in D at r4c3 or r4c4. D therefore cannot use r5c3, even though that cell need not touch both choices.
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.
A A A A A C B B A A A C B D D C C C D D D D E C D D D E E C F F D E E E
Fixed cats: row 6, column 1. One cat is required in each row, column and region.
Step-by-step walkthrough
2Use a candidate lock
Every candidate in row 3 lies in region C (row 3, column 4; row 3, column 5; row 3, column 6). Its cat must use that shared section. Exclude row 1, column 6; row 4, column 6; row 5, column 6 from the rest of region C.
Before step 2. Exclude 3 cells; then scan for a new single.3Check column 6
column 6 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 3. Place one cat, then exclude 3 other cells.4Use a candidate lock
Every candidate in row 4 lies in region D (row 4, column 3; row 4, column 4). Its cat must use that shared section. Exclude row 5, column 3 from the rest of region D.
Before step 4. Exclude 1 cells; then scan for a new single.5Check column 3
column 3 has only one remaining candidate: row 4, column 3. 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 5. 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 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 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: r1c4, r2c2, r3c6, r4c3, r5c5, r6c1.
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