Three ways to find the next cat
Use the row, column, region and no-touch rules together. These examples describe original arrangements; no competitor answers are used.
1. A region with one candidate
Imagine region 3 has three squares: row 2 columns 1–3. Column 1 already has a cat, and the square in column 2 touches a placed cat. Only row 2, column 3 can hold region 3’s cat. Place it, then rule out the rest of its row and column.
2. A region confined to one row
Suppose region 2’s only remaining candidates are row 4, columns 2 and 5. You cannot yet choose between them, but its cat must be in row 4. Every square in that row outside region 2 can be marked ×. Those marks may leave just one candidate in another region.
3. Two groups reserve two columns
If two unfinished regions can only place their cats in columns 1 and 6, they need both columns: one cat in each. Every other region can be ruled out of columns 1 and 6. Check all remaining candidates before applying this pattern; it does not work if either region still has a candidate in another column.
When a pattern is not enough
Challenge boards sometimes need an assumption check: try a candidate in your reasoning and see whether all remaining cats can still fit. Our “Show a reason” labels this explicitly. It never calls an answer reveal a logical deduction.