How to play Star Battle

Star Battle, also known as Two Not Touch, is a logic puzzle with three rules. This page gives the rules, shows a first move on a real board, and lets you try one.

What are the rules of Star Battle?

  1. Place two stars in every row, every column and every coloured region.
  2. No two stars may touch, not even corner to corner.
  3. Every board has exactly one solution, and it can always be reached by logic. You never need to guess.

On Twin Stars every board is 8×8, 9×9 or 10×10, so a finished board holds 16, 18 or 20 stars.

How do you place a star?

Tap a tile once to mark it with a dot, meaning "no star here". Tap it again to place a star, and a third time to clear it. On a computer, right-click places a star directly. Use Undo if you change your mind.

What does a first move look like?

Start where there is least choice. On the board below, nothing has been placed yet.

Try every way of fitting the remaining stars into the cyan region without two touching. The outlined tile has a star in every one of them, so it is certain.

After any star goes down, every tile touching it is ruled out, and so is the rest of any row, column or region that now has both its stars. The board marks those with faint dots for you.

Try a board

This is a gentle 8×8. Hint explains the next logical step in words; Check tells you whether the stars you have placed so far are right.

Where next?

Read the technique guides for the deductions that solve harder boards, play more boards online, or try today's daily puzzle.