Hard Star Battle answer — September 21, 2026

Full written solution

Every deduction from the walkthrough above, in order. Each technique is explained in the Star Battle strategy guide.

1. Starting position — the grid is split into regions (bold outlines). Each row, column, and region needs exactly two stars, and no two stars may touch.
2. Clump analysis (Region 5): candidate clumps can only just supply the remaining stars (row 2, column 4).
3. Clump analysis (Region 8): candidate clumps can only just supply the remaining stars (row 2, column 2).
4. Clump analysis (Region 5): candidate clumps can only just supply the remaining stars (row 1, column 6).
5. Clump analysis (Region 9): candidate clumps can only just supply the remaining stars (row 4, column 8).
6. Clump analysis (Column 8): candidate clumps can only just supply the remaining stars (row 2, column 7).
7. Clump analysis (Column 7): candidate clumps can only just supply the remaining stars (row 4, column 6).
8. Clump analysis (Column 6): candidate clumps can only just supply the remaining stars (row 2, column 5).
9. Clump analysis (Region 4): candidate clumps can only just supply the remaining stars (row 6, column 4).
10. Clump analysis (Region 7): each clump must supply its full share of stars (row 8, column 6).
11. Mark 3 cells adjacent to stars as X (row 7, column 5).
12. Region completion: 2 stars needed, 2 candidates (row 6, column 7).
13. Mark 1 cell adjacent to stars as X (row 5, column 7).
14. Region completion: 1 star needed, 1 candidate (row 9, column 8).
15. Mark 1 cell adjacent to stars as X (row 8, column 8).
16. Column completion: 1 star needed, 1 candidate (row 4, column 7).
17. Mark 2 cells adjacent to stars as X (row 3, column 6).
18. Region completion: 1 star needed, 1 candidate (row 2, column 8).
19. Column completion: 1 star needed, 1 candidate (row 2, column 6).
20. Mark 1 cell adjacent to stars as X (row 1, column 5).
21. Row 2 complete: Mark 2 remaining cells as X (row 2, column 1).
22. Three candidates in a column: Middle cell can't hold a star (row 5, column 5).
23. Column completion: 2 stars needed, 2 candidates (row 4, column 5).
24. Mark 3 cells adjacent to stars as X (row 3, column 4).
25. Region completion: 1 star needed, 1 candidate (row 3, column 3).
26. Mark 2 cells adjacent to stars as X (row 3, column 2).
27. Region completion: 1 star needed, 1 candidate (row 6, column 5).
28. Region completion: 2 stars needed, 2 candidates (row 3, column 1).
29. Region completion: 1 star needed, 1 candidate (row 5, column 2).
30. Mark 3 cells adjacent to stars as X (row 6, column 1).
31. Row 4 complete: Mark 1 remaining cells as X (row 4, column 9).
32. Row completion: 1 star needed, 1 candidate (row 5, column 9).
33. Mark 1 cell adjacent to stars as X (row 6, column 9).
34. Region completion: 1 star needed, 1 candidate (row 7, column 9).
35. Blocking rule: This position would block too many candidates (row 8, column 2).
36. Clump analysis (Column 4): candidate clumps can only just supply the remaining stars (row 8, column 3).
37. Clump analysis (Column 4): each clump must supply its full share of stars (row 1, column 4).
38. Mark 1 cell adjacent to stars as X (row 1, column 3).
39. Column completion: 1 star needed, 1 candidate (row 7, column 3).
40. Mark 2 cells adjacent to stars as X (row 7, column 2).
41. Region completion: 1 star needed, 1 candidate (row 9, column 4).
42. Row 7 complete: Mark 1 remaining cells as X (row 7, column 1).
43. Row completion: 1 star needed, 1 candidate (row 8, column 1).
44. Mark 2 cells adjacent to stars as X (row 9, column 1).
45. Column 1 complete: Mark 1 remaining cells as X (row 1, column 1).
46. Region completion: 1 star needed, 1 candidate (row 1, column 2).
47. Solved! Every row, column, and region has its two stars, none touching.