The elimination technique is the single most important strategy in Star Battle. Master this technique and you'll be able to solve most puzzles. It's the foundation that all other strategies build upon.

What is the Elimination Technique?

The elimination technique is simple in concept: systematically identify cells where stars CANNOT go, until you find cells where stars MUST go.

Instead of guessing where stars might be, you prove where they can't be. What remains must be the solution.

Why Elimination Works

Star Battle puzzles have exactly one solution. This means every cell either:

  • Must have a star (it's the only possibility)
  • Cannot have a star (it's been eliminated)

There's no "maybe." Through systematic elimination, you convert unknowns into certainties.

The Basic Elimination Process

Step 1: Mark Stars That Touch

Whenever you place a star, immediately mark all 8 adjacent cells (including diagonals) as impossible. These cells form a "no-star zone" around every placed star.

Step 2: Mark Completed Rows/Columns/Regions

When any row, column, or region has 2 stars, mark ALL remaining cells in that row/column/region as impossible. They've reached their quota.

Step 3: Check for Forced Stars

After eliminating, check if any row, column, or region has exactly 2 remaining possible cells. If so, both of those cells MUST have stars.

Step 4: Repeat

New star placements create new eliminations, which may force new star placements. This cascade continues until the puzzle is solved.

Advanced Elimination Techniques

The Region Squeeze

If a region can only place its stars within a specific row (or column), eliminate all other cells in that row that belong to OTHER regions. Those cells can't have stars because this region "claims" that row.

The Row/Column Squeeze

Conversely, if a row can only place its stars within a specific region, eliminate all other cells in that region outside this row.

Combined Constraint Elimination

Look for cells where multiple constraints overlap. A cell might seem possible when looking at the row alone, but be impossible when you also consider its region. Always check ALL constraints.

Common Elimination Patterns

The 2-Cell Region Row

If a region only has 2 cells in a particular row, and those cells aren't adjacent, both might need stars. Check if this is consistent with other constraints.

The Diagonal Block

If two stars are placed diagonally with only one cell between them, that middle cell is eliminated (it touches both stars diagonally).

The Corner Trap

Corner cells touch only 3 other cells. If all three are eliminated, the corner must have a star. If the corner has a star, all three adjacent cells are eliminated.

Practice Exercise

Try this systematic approach on your next puzzle:

  1. Scan all regions - mark any obvious eliminations
  2. Check each row left to right - how many possible cells remain?
  3. Check each column top to bottom - how many possible cells remain?
  4. When you find a row/column/region with exactly 2 possibilities, place stars
  5. After each star placement, immediately mark adjacent cells
  6. Return to step 1 and repeat

Why This Beats Guessing

Guessing might work sometimes, but:

  • You might guess wrong and waste time backtracking
  • You don't learn techniques for harder puzzles
  • You miss the satisfaction of logical deduction
  • You can't know if your solution is correct without checking

Systematic elimination always works and always proves your solution is correct.

Put It Into Practice

The elimination technique becomes automatic with practice. Start with our easy daily puzzle and consciously apply each step until it feels natural.

Elimination is the first rung on a ladder: see where it fits alongside every other move in the illustrated Star Battle strategy guide.