Two-star Star Battle › Guide

Two-Star Star Battle Strategy: A Worked 10×10

By Cheng Xu · Published 2026-11-03

To solve two-star Star Battle, find the non-touching pairs that can fit in each row, column and region. Eliminate pairs that conflict with other units; place a star only where every remaining pair in a unit includes that cell.

Each unit needs exactly two stars. Stars never touch, even diagonally. On a 10×10 board the solution has 20 stars. If you are coming from Queens, the important change is that a unit still needs another star after you place its first.

Four deductions to look for first

Finish a unit only after its second star

Once a row, column or region contains two stars, mark its other cells empty. Around each star, mark every neighbouring cell empty, including the diagonals. One star alone does not empty the rest of its row or region.

Use the 2×2 limit

Any two cells in a 2×2 block touch at an edge or corner, so the block holds at most one star. It may hold zero. Only an additional counting argument can prove it holds exactly one. This also explains why a whole two-star region cannot fit inside one 2×2 block.

Keep possible pairs, not just possible cells

If a region's only available cells are three consecutive cells in one row, its two stars must occupy the two ends: the middle touches both. More generally, a cell in every remaining pair is a star; a cell in no remaining pair is empty.

Compare capacities across units

Two regions contained entirely within the same two rows require four stars and use those rows' full four-star quota. Any other cells in those rows are empty. The same reasoning applies to columns. For less tidy shapes, compare individual possible pairs instead.

A complete 10×10 puzzle in seven rounds

This is an advanced worked example of comparing possible pairs, from a blank board to all 20 stars. Rows run top to bottom and columns left to right; R1C2 means row 1, column 2. A–J label the regions. Dots mean empty, and outlined cells are new marks. Keep the marks from earlier rounds.

Play this exact puzzle →

Start at the top: region A occupies R1C2–R1C9 and must contain two stars. Those are already the two stars needed by row 1, so R1C1 and R1C10 are empty. We do not yet know the exact pair inside A.

For the full solve, start with every pair of non-touching cells in each row, column and region. Compare two units at a time. Their pairs must agree on shared cells, and no star in one pair may touch a different star in the other. Remove a pair if it has no compatible pair left in the other unit. Repeat these comparisons as the lists shrink.

Each round below lists the resulting marks and the remaining pairs that justify them. The optional comparison ledger records every removed pair in order: the named other unit has no compatible pair at that point. Some rounds prove only empty cells; that is useful progress.

The finished board contains 20 stars: two per row, column and region, with none touching. Every placement above follows from eliminating incompatible pairs, without choosing a speculative pair.

Common two-star mistakes

• Clearing a row after its first star: it still needs a second one.
• Treating every 2×2 as occupied: the rule is at most one, not exactly one.
• Blocking a whole diagonal: stars cannot touch; distant diagonal cells remain possible.
• Checking regions alone: a pair must also fit its rows, columns and neighbouring stars.
• Calling a plausible pair certain: a pair that survives one comparison is only a candidate. Keep all remaining candidates until a deduction forces a mark.

Keep practising

Play another two-star puzzle →

Need a gentler introduction? Try one-star Queens strategy and read Queens vs Star Battle vs N-Queens.

About this example

The board is an original Solvedle practice puzzle, separate from the daily trio. Its unique solution is checked independently of the pair deductions. The complete comparison ledger is included so every round can be followed from the original board. Grandmaster Puzzles explains the underlying Star Battle rules.