A small step toward a better solve.
Start with the rules. Build up to a full puzzle.
Learn at your own pace with clear explanations and original examples. Each lesson builds a practical skill you can use right away.

Featured lesson
A first puzzle, explained
One cat per row, column and region. No edge or corner contact. Clear examples and a real first step.
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1The rules
Learn the row, column, region and no-touch rules, and make your first moves.
2Candidate marks
Use × as a record of exclusions, and distinguish notes from fixed facts.
3The no-touch rule
Understand edge contact, corner contact and distant diagonal placements.
Spot the next move
4Single candidates
Find forced cats by checking the remaining cells in a row, column or region.
5Row and column scans
Cross-check constraints instead of solving one region in isolation.
6Region-line locks
Exclude candidates using the intersection of a region and a row or column.
7Narrow regions
Use region shape to focus attention while checking all row and column constraints.
Put it together
Worked puzzles
105×5 walkthrough
Follow gm-5-0003 through shared neighbors, a bottom-region lock and the first forced cat.
116×6 walkthrough
Solve original gm-6-0002 by reserving regions B and C, excluding shared neighbors and following column singles.
128×8 walkthrough
Follow original gm-8-0008 through a C reservation, a later F reservation and a separate shared-neighbor deduction.