Use the three completed upper rows as constraints

Original puzzle gm-6-0004

By GridMew · Published 15 October 2026 · Updated 16 October 2026

6 × 6 intro

Read the starting position, follow the deductions, and check the move that is easy to misread.

Puzzle board · starting state

gm-6-0004: 6×6 regional boardAAAACCBBAACCBAACCCBDACCCDDFCEEDDFFEE

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 givens fill rows 1–3. The remaining work is below them, but their columns, regions and touching cells still determine which lower-row candidates survive. Start with row 4 rather than treating the lower half as a separate puzzle.

6×6 · 3 fixed cats · 3 explained deductions. Region sizes: A: 9 · B: 4 · C: 11 · D: 5 · E: 4 · F: 3.

A deduction worth checking

r4c2 is forced. It rules out r5c3 by contact and column-2 cells farther down, directing row 5 toward r5c6.

gm-6-0004: 6×6 regional boardA×A×A×AC×C×BB×A×A×C×C×B×A×A×C×CC×B×DA×C×C×C×D×DFC×E×ED×DFF×E×E
Position before step 1. Review the technique.
A move to double-check · r5c3

r5c3 remains in a different region from r4c2, yet the two cells share a corner. Do not let the horizontal region boundary hide that contact.

gm-6-0004: 6×6 regional boardA×A×A×AC×C×BB×A×A×C×C×B×A×A×C×CC×B×DA×C×C×C×D×DFC×E×ED×DFF×E×E

Green marks the cell being discussed, not a cat to place. This is the position before step 1; 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 C C
B B A A C C
B A A C C C
B D A C C C
D D F C E E
D D F F E E

Fixed cats: row 3, column 5; row 2, column 1; row 1, column 4. One cat is required in each row, column and region.

Step-by-step walkthrough

1Check row 4

row 4 has only one remaining candidate: row 4, column 2. Every other cell is excluded by earlier placements or deductions. Place the cat here.

gm-6-0004: 6×6 regional boardA×A×A×AC×C×BB×A×A×C×C×B×A×A×C×CC×B×DA×C×C×C×D×DFC×E×ED×DFF×E×EBefore step 1. Place one cat, then exclude 3 other cells.

2Check row 5

row 5 has only one remaining candidate: row 5, column 6. Every other cell is excluded by earlier placements or deductions. Place the cat here.

gm-6-0004: 6×6 regional boardA×A×A×AC×C×BB×A×A×C×C×B×A×A×C×CC×B×DA×C×C×C×D×D×F×C×E×ED×D×FF×E×EBefore step 2. Place one cat, then exclude 1 other cells.

3Check row 6

row 6 has only one remaining candidate: row 6, column 3. Every other cell is excluded by earlier placements or deductions. Place the cat here.

gm-6-0004: 6×6 regional boardA×A×A×AC×C×BB×A×A×C×C×B×A×A×C×CC×B×DA×C×C×C×D×D×F×C×E×ED×D×FF×E×E×Before step 3. 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.

gm-6-0004: 6×6 regional boardAAAACCBBAACCBAACCCBDACCCDDFCEEDDFFEE

Cat positions: r1c4, r2c1, r3c5, r4c2, r5c6, r6c3.

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How this puzzle and its reasoning are verified