Star Battle

How to play Star Battle online

1. Choose a Size above the board: 5×5, 6×6, 8×8 or 10×10 · 2★. The default is 8×8 · 1★.
2. Choose a Difficulty: Easy, Medium or Hard.
3. Press New puzzle. “Generating…” shows while the new board is made.
4. Click or tap a cell to place a star. Click it again to clear it.
5. Right-click, or use the Dot chip, to mark a cell you know has no star.
6. After each star, dot out the cells it rules out. This keeps the board easy to read.
7. Press Hint when you are stuck. It highlights the cells involved and explains the rule in one sentence.
8. Press Check to see cells that break a rule or differ from the solution in red, or ‘No mistakes so far’ with the percentage done.
9. Use Undo and Redo to step back and forward. Restart clears the board but keeps the same puzzle. Show solution reveals the answer.

The keyboard works too: arrow keys move, Space places a star, X marks a dot and Backspace clears. Ctrl+Z is Undo and Shift+Ctrl+Z is Redo (Cmd on a Mac). On a phone, the Star and Dot chips above the board choose what a tap does, and Move lets you scroll a zoomed board. Zoom out, Fit and Zoom in change the board size. Print gives you the puzzle on its own page, and you can tick ‘Print the answer page too’ to add the solution. Copy link creates a link to the exact same puzzle, so you can continue on another device.

Star Battle rules

An n×n grid is cut into n outlined regions. Place stars so that every row, every column and every region holds exactly the same number of stars, and no two stars touch, not even diagonally. On 5×5, 6×6 and 8×8 boards, that means one star per row, column and region. The tool shows rule breaks in red as you play, including two touching stars and any line or region with too many stars.

How to solve star battle puzzles

Start by finding a star you can be sure of, then let it rule out cells. The tool names its solving techniques, and the simplest ones come first. Neighbours: a star rules out the up to 8 cells around it. Full: once a row, column or region has all its stars, every other cell in it is empty. Only: when a row, column or region has exactly as many open cells as stars it still needs, all those open cells are stars. A one-cell region is always a star. The generator’s first hint on a 5×5 Easy puzzle uses this idea: the highlighted region has exactly as many open cells as stars it needs, so every open cell in it is a star.

Harder puzzles need three more ideas. Crowd: a cell that, as a star, would rule out so many open cells of a region that the region could no longer get its stars cannot be a star. Confine: if all open cells of a region sit in one row (or column), that row’s star must come from the region, so the row’s other cells are empty. Counting: if k regions lie entirely inside k rows, those rows’ stars all belong to those regions, so their other cells are empty. Small regions and regions squeezed into one or two rows are good places to begin.

What makes a star battle puzzle easy or hard?

On 1-star boards, Easy puzzles are solved with neighbours, full and only alone. Medium puzzles also need crowd and confine. Hard puzzles need counting or trial and error. The 10×10 board with 2 stars is one step harder at every level, because no row, column or region is small enough to start with the easy rules. There, Easy needs confine or crowd, Medium needs counting, and Hard needs trial and error.

What does 2 star mean?

“2★” means each row, column and region holds exactly two stars. On the 10×10 · 2★ board, that gives two stars in every row and every column, and two in every one of the 10 regions. The total is 20 stars, and two stars still cannot touch.

Is star battle like sudoku?

Star battle is similar to sudoku in one way: it is a logic puzzle with one answer, and you solve it by deduction rather than guessing. Both puzzles also require each line and block to follow an exact count. The differences are clear, though. Sudoku uses the digits 1 to 9, while star battle uses only stars and dots. Star battle regions are irregular shapes rather than 3×3 boxes. Its no-touching rule has no direct sudoku equivalent.

Frequently asked questions

Is star battle free, and do I need an account?

Yes. The tool is free, and there is no account or sign-up. Your progress and settings are saved in your browser and restored when you return.

Can I play star battle on my phone?

Yes. It works on phones, tablets and computers. On a phone, the Star and Dot chips choose what a tap does, and Move lets you scroll a zoomed board.

Can I print a star battle puzzle?

Yes. Press Print to get the puzzle on its own page, with its size, difficulty and rules. Tick ‘Print the answer page too’ to add the solution, and choose Save as PDF in the print dialog if you want a file. A4 and Letter both work.

Does every star battle puzzle have one solution?

Yes. Each puzzle is generated in your browser and kept only when the site’s solver proves it has exactly one solution. You can always finish it by logic alone.

Why is a star marked in red?

It breaks a rule: two stars touch, or a row, column or region has too many stars. Move or clear the star, or press Undo. You can turn off ‘Show rule errors as I play’ for a harder game.

How do I undo a wrong star?

Press Undo, or Ctrl+Z (Cmd+Z on a Mac). Redo is Shift+Ctrl+Z. If you have already made a wrong mark, Hint points at it first.

How can I share the same puzzle?

Press Copy link. The link includes the size, seed and difficulty, so anyone who opens it gets exactly the same puzzle.

Can I use star battle puzzles from here in a book or Etsy listing?

Yes. Star Battle puzzles from this page are royalty-free for personal, classroom and commercial use, including KDP books, Etsy printables, Teachers Pay Teachers and print-on-demand. No credit is required. The only thing you may not do is copy the generator or the site itself to run a competing service; see the terms.

Related tools

• Shikaku: try this if you like splitting a grid into rectangles using numbers.
• Norinori: a good next step if you enjoy shading regions under strict placement rules.
• Slitherlink: pick this when you want a loop-drawing puzzle with number clues.
• Bridges puzzle (Hashi): use this for connecting islands with bridges that follow counting rules.
• Binary puzzle (Binairo): choose this for another logic puzzle with a strict row and column balance.
• Masyu: try this if you want to draw a single loop through marked cells.
• Hitori: a good match when you enjoy crossing out numbers while keeping the grid connected.
• Nonogram: play online when you prefer solving pictures from row and column clues.
• Mosaic puzzle: pick this when you want to shade cells to match the numbers around them.
• LITS puzzle: choose it to shade one tetromino in every region instead of placing stars.