How to play

How to play Star Battle

Star Battle, also known as Two Not Touch, is a placement puzzle: put two stars in every row, column and colour region without any two touching. Here are the rules, the marking system and the deductions that solve any board without guessing.

1. Two stars per row, column and colour

   The board is an n×n grid split into n coloured regions. Place exactly 2n stars so that every row, every column and every region contains exactly two.

2. Stars never touch

   No two stars may be adjacent, not even diagonally. Every cell around a star, all eight of them, must stay empty. Two stars can share a diagonal as long as there is a gap between them.

3. Mark what's impossible

   Tap once to mark a cell with ✕, meaning "no star here". Drag across cells to mark several. Tap again to place a star, and a third time to clear the cell. With auto-place on (the default), a new star crosses out its eight neighbours, and when a row, column or region reaches its second star the rest of it is crossed out too.

4. Count the room

   The new idea compared with Queens: a region that still needs two stars and has only three free cells in a line must use the two ends, because the middle would touch both. Whenever you know how many stars a slice of the board must hold, check how many ways there are to fit them without touching.

5. Ask for a hint when stuck

   A hint never guesses. It finds the next deduction, explains it in one sentence, highlights the cells involved and marks them. The daily puzzle gives three; unlimited mode has no limit.

The deductions, in order

Rule	What it means
Neighbours	The eight cells around a star are out.
Full unit	A row, column or region that has both its stars: everything else in it is out.
Exact fit	A unit with exactly as many free cells as stars it still needs: they are all stars.
Only one way	A unit needs two stars and its free cells allow a single placement that keeps them apart: place both. Cells that no legal placement uses are out.
Confinement	A region whose free cells all sit in one row (or column), and the row needs exactly as many stars as the region: the rest of the row is out. Two regions confined to the same two rows own both rows, and so on.
Touches everything	A unit needs one more star; a cell adjacent to every free cell of that unit can't hold a star. If a unit needs two, a cell that touches every legal pair is out too.
What if	Imagine a star in a cell and follow the forced moves. If some row, column or region ends up with too few free cells or too many stars, the cell is out. Hard boards need a few of these.

Strategy tips

• Small regions first. A region of three or four cells has very few ways to hold two stars, and each way crosses out a lot.
• Count slices. Two rows hold four stars. If two regions live entirely inside those rows and need four between them, no other region can use the rows.
• Watch the sweep. With auto-place on, the second star in a row crosses out the whole row. If that sweep leaves another unit with too little room, your star was wrong.
• Red means touching or doubled up. A red star breaks a rule right now. Undo it before continuing.
• Hints teach. If you learn the deduction a hint used, you'll spot it yourself next time.

Daily, unlimited and archive

Every day at local midnight there is one new puzzle. The board follows the week:

Day	Board
Monday	8×8 · Easy
Tuesday	8×8 · Medium
Wednesday	9×9 · Medium
Thursday	9×9 · Hard
Friday	10×10 · Medium
Saturday	10×10 · Hard
Sunday	10×10 · Hard

Solve the daily to extend your streak. Unlimited serves boards from 8×8 to 10×10 in four difficulties with no limit, and the archive keeps every past day playable.

Star Battle, Two Not Touch and Queens

Star Battle first appeared at the 2003 World Puzzle Championship. The New York Times prints the 10×10 two-star version as Two Not Touch, and LinkedIn's Queens is the one-star version with coloured regions. Puzzlune has both: Queens for one star, this page for two. Puzzlune is not affiliated with either publisher.

Play today's Star Battle