Star Battle

How to play Star Battle

Star Battle is a logic puzzle for one player. The square grid is split into regions with thick borders, and each region has its own soft colour. There are as many regions as rows. You place stars, and the rules decide exactly where they go.

Goal

Place stars so that:

• Every row has the same number of stars.
• Every column has that number of stars.
• Every region has that number of stars.
• Stars never touch, not even on a corner.

On Easy and Medium the number is one star. On Hard it is two stars per row, column and region. The line under the grid always tells you the rule for the current puzzle. Each puzzle has exactly one answer.

Step by step

1. Tap a square once to place a star. Tap again to change it into a dot, which means “no star here”. Tap a third time to clear it. Right-click also places a dot.
2. On a keyboard, move with the arrow keys. Press S for a star, D for a dot, Space to cycle and Backspace to clear.
3. After each star, put dots in all eight squares around it, and in the rest of its row, column and region once they are full.
4. Stars that break a rule, by touching or by crowding a line or region, turn red.
5. When a row, column or region gets all its stars, it flashes.
6. Press Undo to take back any step.

Levels

Easy is a 6×6 grid with one star per line. Medium is 8×8 with one star. Hard is 10×10 with two stars in every row, column and region, the size used in many puzzle contests.

End of the game

You win when every star is in place. The timer stops and shows your time. Your puzzle is saved in this browser, so you can come back later. For another grid puzzle with simple rules, try Tents.

Strategy tips

• Start with small regions. A region of two or three squares has very few places for its star. Squares that would touch every option can be dotted.
• Regions inside one line. If a region lies completely in one row, its star is in that row. Dot the rest of the row outside that region.
• Count regions and lines. If two regions fit together inside two rows, they use all the stars of those rows. Every other square in those rows is empty.
• Look at 2×2 blocks. Stars cannot touch, so any 2×2 block holds at most one star. This helps a lot in two-star puzzles.
• Dot generously. Dots are free. Marking squares that cannot hold a star makes the next step easier to see.
• Test a square. If putting a star somewhere would leave a region with no room, that square must be a dot.