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 8 other cells.An upper-left region leads to a distant column single
Original puzzle gm-8-0004
By GridMew · Published 15 October 2026 · Updated 16 October 2026
8 × 8 intro
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 given at r7c2 occupies column 2, reducing A’s top-left pair to r1c1. Update the entire first row and column before looking for the next single.
8×8 · 2 fixed cats · 6 explained deductions. Region sizes: A: 2 · B: 2 · C: 16 · D: 14 · E: 11 · F: 7 · G: 8 · H: 4.
A deduction worth checking
After column 8 resolves at r2c8, column 6 has only r8c6. That lower placement helps narrow E toward r5c3.
A move to double-check · r8c5
r8c5 is removed by the row-8 quota when r8c6 is placed. The two positions are also neighbors, but row completion alone settles it.
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 A C C C C C C E E C C C C D B E E C C C D D B E E E C C D D D E E E C F D D D G G E F F D D D G G G F F H H D G G G F F H H D
Fixed cats: row 7, column 2; row 4, column 7. One cat is required in each row, column and region.
Step-by-step walkthrough
2Check column 8
column 8 has only one remaining candidate: row 2, column 8. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 2. Place one cat, then exclude 4 other cells.3Check column 6
column 6 has only one remaining candidate: row 8, column 6. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 3. Place one cat, then exclude 2 other cells.4Check region E
region E has only one remaining candidate: row 5, column 3. 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 row 6
row 6 has only one remaining candidate: row 6, column 5. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 5. Place one cat, then exclude 1 other cells.6Check row 3
row 3 has only one remaining candidate: row 3, column 4. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 6. 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, r2c8, r3c4, r4c7, r5c3, r6c5, r7c2, r8c6.
Try another puzzle
A column-first route reaches the lower-right regions
gm-8-0011 · 8×8 · intro
Practice single-candidate placements on another 8×8 board.
Read this walkthrough →A bottom-right cat clears a path through row 3
gm-6-0005 · 6×6 · intro
Transfer single-candidate placements to a 6×6 grid; compare how the candidates change.
Read this walkthrough →A shared neighborhood settles the right edge
gm-6-0007 · 6×6 · challenge
Compare this route with shared-neighbor exclusions, and check why that different rule is needed.
Read this walkthrough →