GridMew1Check region F
region F has only one remaining candidate: row 6, column 2. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 1. Place one cat, then exclude 5 other cells.A one-cell region sends information across the board
Original puzzle gm-8-0007
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.
Region F is just r6c2. Its placement, alongside the two givens, reduces H to r8c3. Follow these lower anchors before examining the upper regions.
8×8 · 2 fixed cats · 6 explained deductions. Region sizes: A: 4 · B: 8 · C: 9 · D: 20 · E: 12 · F: 1 · G: 4 · H: 6.
A deduction worth checking
Region A then forces r1c5. It removes the upper-right row candidates and reaches down column 5, preparing region G.
A move to double-check · r7c5
r7c5 remains far from r1c5, but the shared column rules it out. The diagonal no-touch rule is not a substitute for that full-column check.
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.
C C A A A B B B C C A D D B B B C C C D D D D B C C E D D D D B E E E E E D D D E F E E E D D D E E H H G G D D H H H H G G D D
Fixed cats: row 3, column 1; row 5, column 4. One cat is required in each row, column and region.
Step-by-step walkthrough
2Check region H
region H has only one remaining candidate: row 8, column 3. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 2. Place one cat, then exclude 6 other cells.3Check region A
region A has only one remaining candidate: row 1, column 5. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 3. Place one cat, then exclude 6 other cells.4Check region G
region G has only one remaining candidate: row 7, column 6. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Before step 4. Place one cat, then exclude 3 other cells.5Check region D
region D has only one remaining candidate: row 4, 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 2
row 2 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 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: r1c5, r2c8, r3c1, r4c7, r5c4, r6c2, r7c6, r8c3.
Try another puzzle
A singleton turns a large board into a sequence of singles
gm-8-0003 · 8×8 · intro
Practice single-candidate placements on another 8×8 board.
Read this walkthrough →Resolve the outside rows before the top centre
gm-5-0010 · 5×5 · intro
Transfer single-candidate placements to a 5×5 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 →