How to solve Star Battle puzzles
Four techniques solve every Pencilmark puzzle, from a five-by-five to an expert nine-by-nine. Learn them in order.
The four techniques
Pencilmark's solver uses four techniques, ordered from simplest to hardest. The hint button always suggests the simplest one that applies, and the difficulty label of a puzzle reflects the hardest technique it needs.
| Technique | What it does | Used in |
|---|---|---|
| Last candidate | Every row, column and region needs a star. | Easy and above |
| Confined region | If every remaining cell of a region sits in one row or column, that line's star belongs to the region and all other cells of that line are out. | Easy and above |
| Neighbor squeeze | Pretend a star sits in a cell. | Medium and above |
| Region group | When two or three rows or columns can only hold stars from the same number of regions, those regions are used up and their other cells can be crossed out.. | Hard and expert |
A solving routine
- Scan the small regions. A region with two cells in one row removes that row from everything else.
- Place obvious stars (last candidate) and cross out their surroundings immediately.
- Check lines against regions for confined regions.
- Test the awkward cells with a neighbor squeeze.
- Count regions in groups of lines when nothing else moves.
Why logic is enough
A puzzle is only worth solving if its deductions exist. Pencilmark's solver replays each grid using only these techniques and refuses puzzles that need more. Read how solver certification works.
FAQ
How many techniques does Star Battle need?
Easy and medium puzzles need only last candidate, confined regions and neighbor squeeze. Hard and expert puzzles add region groups of two or three lines.
Do I ever need to guess?
Not in Pencilmark. Every puzzle is verified to be solvable by these techniques alone.
What should I look for first?
The smallest regions, then lines that are almost full. Two-cell regions are especially strong.