Puzzle rules

Star Battle rules: one star or two?

Star Battle is a grid logic puzzle. Place the required number of stars in every row, column and outlined region, without allowing any two stars to touch.

The rules shared by Star Battle puzzles

1. Each row must contain the required number of stars.
2. Each column must contain that same number.
3. Each region must also contain that number, regardless of its size or shape.
4. No two stars may share an edge or a corner. There is never more than one star in a square.

Regions are the areas bounded by the puzzle’s heavy lines, colours, or both. A region may spread across several rows and columns; count it as a whole.

One-star and two-star puzzles

In a one-star puzzle, a placed star finishes its row, column and region. In a two-star puzzle, those areas may still need a second star. Crossing out an entire row after its first star would lose valid choices.

Sprig uses the one-star rules. Each Sprig is the star for its row, column and coloured region. The browser practice puzzles are 6 × 6, 7 × 7 or 8 × 8.

What does “not touching” include?

It includes all eight neighbouring squares: above, below, left, right and the four diagonal corners. Two stars separated by at least one square can share a diagonal, provided the other rules allow it. Star Battle does not ban an entire diagonal.

How do you know a puzzle is finished?

Count the stars in every row, column and region, then check that no pair touches. Each count must match the puzzle’s target. A correct total on the whole board alone is not enough.

How do you start solving?

Look at the regions with the fewest available squares, keep track of the count still needed, and mark squares ruled out by confirmed stars. Our Star Battle tips focus on the one-star version, with a worked Sprig example.

For a two-star reference, the World Puzzle Federation’s 2022 Round 1 instruction booklet includes Star Battle rules and an example.