Star Battle (frequently referred to in the United States as Two Not Touch, and sharing mechanics with games like LinkedIn Queens) is a pure deduction logic puzzle. Unlike Sudoku, which relies on numbers from 1 to 9, Star Battle is visual and spatial.

Every puzzle consists of an $N \times N$ grid divided into $N$ distinct contiguous geometric regions. Your goal is to place a predetermined number of stars (usually 1 star for 8x8 grids, or 2 stars for classic 10x10 grids) in every row, column, and marked region.

The Three Golden Rules of Star Battle

1.Row & Column Quota: Exactly $K$ stars must be placed in each horizontal row and each vertical column (e.g. 2 stars in 10x10).
2.Region Quota: Exactly $K$ stars must be located within every bold bordered shape/region.
3.The “Two Not Touch” Adjacency Rule: Stars can never touch each other—horizontally, vertically, or diagonally. When you place a star, all 8 surrounding neighbor cells are immediately eliminated and must be marked with a cross (✕).

Essential Solving Strategy for Beginners

Tip #1: Look at 1-cell and 2-cell thick regions

In a 2-star puzzle, a region spanning only 2 adjacent rows can absorb at most 2 stars. If multiple regions align along the grid borders, you can eliminate entire rows by counting total region stars (the pigeonhole deduction).

Tip #2: Mark crosses liberally

Star Battle is won by elimination. When a cell cannot possibly contain a star, mark it with ✕ immediately. As cells are crossed off, remaining empty cells in rows and regions become forced star placements.