The rules in short
- Each row and each column holds the same number of stars.
- Each outlined region holds that same number of stars.
- Stars never touch, not even diagonally.
The number depends on the puzzle. Small grids use one star per line. The classic 10×10 uses two. A well-made puzzle has exactly one solution, and you can reach it by logic alone, with no guessing. Our guide on how to play walks through the rules with pictures.
Where it comes from
Hans Eendebak created Star Battle for the 2003 World Puzzle Championship in the Netherlands. It has been a regular at puzzle competitions ever since, because the rules take a minute to learn and the hardest grids can occupy strong solvers for a long time.
The puzzle reached a much wider audience when The New York Times began publishing it under the name Two Not Touch. LinkedIn's Queens game uses the one-star format with coloured regions.
Grid sizes
| Grid | Stars per line | Total stars | Good for |
|---|---|---|---|
| 5 × 5 | 1 | 5 | Learning the rules in a minute |
| 8 × 8 | 1 | 8 | A quick break, and your first techniques |
| 10 × 10 | 2 | 20 | The classic daily puzzle |
| 14 × 14 | 3 | 42 | A long session for experts |
Why people like it
Star Battle has the appeal of Sudoku with no numbers to keep in your head. You look at shapes, count a little, and each deduction opens up the next one. Because a star rules out all of its neighbours, one good move can clear a big part of the board, which makes it satisfying to solve.
On this site, there is one more reward. Each region you finish turns to night, and your finished board becomes a constellation that you can keep in your Atlas.
Star Battle and Sudoku compared
| Star Battle | Sudoku | |
|---|---|---|
| What you place | Stars | Digits 1 to 9 |
| Regions | Irregular shapes, different in every puzzle | Fixed 3×3 boxes |
| Extra rule | Stars can't touch | No repeats in a row, column or box |
| Starts with | An empty grid | Some digits given |