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