Hard Star Battle answer — September 14, 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. Blocking rule: This position would block too many candidates (row 2, column 2).
3. Blocking rule: This position would block too many candidates (row 3, column 5).
4. Blocking rule: This position would block too many candidates (row 6, column 5).
5. Clump analysis (Region 3): candidate clumps can only just supply the remaining stars (row 2, column 3).
6. Clump analysis (Region 6): candidate clumps can only just supply the remaining stars (row 2, column 5).
7. Clump analysis (Region 8): candidate clumps can only just supply the remaining stars (row 6, column 6).
8. Clump analysis (Region 9): candidate clumps can only just supply the remaining stars (row 8, column 2).
9. Joint analysis (Region 9 + Row 8): every legal combination of their stars rules these cells out (row 9, column 6).
10. Joint analysis (Row 8 + Region 7): every legal combination of their stars rules these cells out (row 8, column 8).
11. Clump analysis (Region 8): candidate clumps can only just supply the remaining stars (row 4, column 5).
12. Three candidates with two adjacent: Isolated candidate must hold a star (row 3, column 4).
13. Mark 3 cells adjacent to stars as X (row 2, column 4).
14. Generalized counting (rows 1-3): region star limits exclude these cells (row 3, column 9).
15. Clump analysis (Region 4): candidate clumps can only just supply the remaining stars (row 5, column 7).
16. Composite container (columns 1-3): Regions 3 and 5 are confined here, so the leftover cells owe exactly 2 of the band's 6 stars - a star on these cells would crowd them out (row 6, column 2).
17. Lookahead: Placing star here leads to contradiction - Region 7 would only have room for 1 of the 2 stars it still needs (row 8, column 7).
18. Crowding (Row 8): a star here would leave too little room for its 2 remaining stars (row 7, column 2).
19. Blocking rule: This position would block too many candidates (row 9, column 4).
20. Three candidates with two adjacent: Isolated candidate must hold a star (row 9, column 5).
21. Clump analysis (Region 7): candidate clumps can only just supply the remaining stars (row 9, column 1).
22. Region completion: 1 star needed, 1 candidate (row 8, column 3).
23. Mark 2 cells adjacent to stars as X (row 7, column 3).
24. Three candidates with two adjacent: Isolated candidate must hold a star (row 6, column 3).
25. Mark 3 cells adjacent to stars as X (row 5, column 2).
26. Column 3 complete: Mark 1 remaining cells as X (row 1, column 3).
27. Column completion: 1 star needed, 1 candidate (row 1, column 4).
28. Mark 1 cell adjacent to stars as X (row 1, column 5).
29. Three candidates with two adjacent: Isolated candidate must hold a star (row 5, column 5).
30. Mark 2 cells adjacent to stars as X (row 4, column 6).
31. Column 5 complete: Mark 1 remaining cells as X (row 7, column 5).
32. Region completion: 1 star needed, 1 candidate (row 7, column 6).
33. Mark 2 cells adjacent to stars as X (row 6, column 7).
34. Blocking rule: This position would block too many candidates (row 7, column 8).
35. Blocking rule: This position would block too many candidates (row 7, column 9).
36. Row completion: 1 star needed, 1 candidate (row 7, column 1).
37. Mark 2 cells adjacent to stars as X (row 6, column 1).
38. Row completion: 1 star needed, 1 candidate (row 8, column 9).
39. Mark 1 cell adjacent to stars as X (row 9, column 8).
40. Region completion: 1 star needed, 1 candidate (row 9, column 7).
41. Two-option rule: Cell adjacent to both candidates (row 5, column 8).
42. Two-option rule: Cell adjacent to both candidates (row 5, column 9).
43. Row completion: 1 star needed, 1 candidate (row 5, column 1).
44. Mark 2 cells adjacent to stars as X (row 4, column 1).
45. Column 1 complete: Mark 2 remaining cells as X (row 1, column 1).
46. Region completion: 2 stars needed, 2 candidates (row 1, column 2).
47. Region completion: 1 star needed, 1 candidate (row 3, column 2).
48. Row 1 complete: Mark 4 remaining cells as X (row 1, column 6).
49. Row 3 complete: Mark 2 remaining cells as X (row 3, column 6).
50. Region completion: 1 star needed, 1 candidate (row 2, column 6).
51. Column completion: 1 star needed, 1 candidate (row 4, column 7).
52. Mark 1 cell adjacent to stars as X (row 4, column 8).
53. Region completion: 1 star needed, 1 candidate (row 4, column 9).
54. Column completion: 2 stars needed, 2 candidates (row 2, column 8).
55. Mark 1 cell adjacent to stars as X (row 2, column 9).
56. Column completion: 1 star needed, 1 candidate (row 6, column 8).
57. Mark 1 cell adjacent to stars as X (row 6, column 9).
58. Solved! Every row, column, and region has its two stars, none touching.