How to play star battle puzzle
- Read the regions and N. The wooden board is divided into shaded regions (thick borders). Each level states how many stars belong in every row, column and region — most boards use N=1; a later challenge uses N=2 on a larger grid. This page ships 16 hand-checked levels from 5×5 to 10×10 (115 stars across all boards).
- Tap to place stars or marks. Tap an empty cell to place a star, tap again to mark it empty (×), tap once more to clear. Marks help you remember cells that cannot hold a star.
- Satisfy the three counts and spacing. Every row, every column and every region must contain exactly N stars. Stars may never share an edge or a corner — the eight-neighbour rule. When both counts and spacing are perfect, the level clears.
- Use Undo, Reset or Hint. Undo reverses the last mark. Reset clears your entries. Hint places one forced star or mark — or a cell from the unique solution. Games that used Hint do not update your best.
Star battle strategy
- Mark cells that touch an already-placed star — those eight neighbours can never hold another star.
- When a row (or column, or region) already has its N stars, mark every remaining empty cell there.
- If a row still needs k stars and only k safe empty cells remain, those cells are all stars (check adjacency first).
- Tiny regions are strong clues: a one-cell region with N=1 forces a star; a region with few cells near existing stars often collapses quickly.
- Hint always agrees with the unique solution, so following it finishes a solvable board.
Why every level is uniquely solvable
We place a full legal star layout (row/column/region counts plus eight-neighbour separation), seed each region from those stars, then grow the region map cell by cell while a backtracking solver still reports exactly one completion. Boards that lose uniqueness are discarded. Unit tests rerun that uniqueness check on every ship.
Hint prefers forced stars or marks from those rules; if several options remain, it reads the stored unique solution — never a second conflicting layout.
More logic puzzles
Like grid logic? Try tents puzzle, binary puzzle, Lights Out, Fillomino or LITS. Chinese speakers can play the 星战谜题 version of this page with the same saved progress.