Hard Star Battle answer — September 5, 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: a star here would touch every other open cell in its region, leaving no room for the region's second star (row 9, column 2).
3. Clump analysis (Region 4): candidate clumps can only just supply the remaining stars (row 6, column 3).
4. Clump analysis (Region 7): candidate clumps can only just supply the remaining stars (row 8, column 2).
5. Clump analysis (Region 9): candidate clumps can only just supply the remaining stars (row 9, column 7).
6. Clump analysis (Region 10): candidate clumps can only just supply the remaining stars (row 2, column 9).
7. Undercounting: 3 regions fit in rows 8-10, eliminate 5 outside candidates (row 8, column 5).
8. Blocking rule: a star here would touch every other open cell in its region, leaving no room for the region's second star (row 6, column 9).
9. Blocking rule: a star here would touch every other open cell in its region, leaving no room for the region's second star (row 7, column 9).
10. Three candidates with two adjacent: Isolated candidate must hold a star (row 7, column 8).
11. Mark 3 cells adjacent to stars as X (row 6, column 7).
12. Clump analysis (Region 4): candidate clumps can only just supply the remaining stars (row 7, column 1).
13. Region completion: 1 star needed, 1 candidate (row 6, column 10).
14. Mark 2 cells adjacent to stars as X (row 5, column 9).
15. Blocking rule: a star here would touch every other open cell in its region, leaving no room for the region's second star (row 3, column 9).
16. Clump analysis (Column 9): candidate clumps can only just supply the remaining stars (row 9, column 8).
17. Three candidates with two adjacent: Isolated candidate must hold a star (row 10, column 7).
18. Mark 2 cells adjacent to stars as X (row 9, column 6).
19. Clump analysis (Column 9): each clump must supply its full share of stars (row 1, column 9).
20. Mark 4 cells adjacent to stars as X (row 1, column 8).
21. Three candidates with two adjacent: Isolated candidate must hold a star (row 3, column 8).
22. Mark 4 cells adjacent to stars as X (row 2, column 7).
23. Column 8 complete: Mark 1 remaining cell as X (row 5, column 8).
24. Clump analysis (Region 1): candidate clumps can only just supply the remaining stars (row 4, column 5).
25. Crowding (Row 8): a star here would leave too little room for its 2 remaining stars (row 9, column 5).
26. Squeeze (rows 7-8): each clump in the band must supply its full share of stars (row 8, column 6).
27. Squeeze (rows 8-9): the band's clumps can only just fit its stars (row 10, column 9).
28. Region completion: 1 star needed, 1 candidate (row 9, column 9).
29. Composite container (rows 1-2): Region 8 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 1, column 2).
30. Squeeze (columns 2-3): the band's clumps can only just fit its stars (row 3, column 5).
31. Clump analysis (Region 6): each clump must supply its full share of stars (row 2, column 3).
32. Squeeze (columns 4-5): the band's clumps can only just fit its stars (row 7, column 3).
33. Column completion: 1 star needed, 1 candidate (row 5, column 7).
34. Mark 3 cells adjacent to stars as X (row 4, column 6).
35. Column completion: 1 star needed, 1 candidate (row 3, column 6).
36. Mark 1 cell adjacent to stars as X (row 2, column 5).
37. Region complete: Mark 1 remaining cell as X (row 5, column 5).
38. Region completion: 1 star needed, 1 candidate (row 1, column 5).
39. Row 1 complete: Mark 1 remaining cell as X (row 1, column 1).
40. Row completion: 1 star needed, 1 candidate (row 2, column 1).
41. Mark 1 cell adjacent to stars as X (row 3, column 1).
42. Row 3 complete: Mark 1 remaining cell as X (row 3, column 10).
43. Region completion: 1 star needed, 1 candidate (row 4, column 10).
44. Clump analysis (Row 4): candidate clumps can only just supply the remaining stars (row 5, column 2).
45. Clump analysis (Region 7): candidate clumps can only just supply the remaining stars (row 4, column 1).
46. Region completion: 1 star needed, 1 candidate (row 6, column 2).
47. Mark 2 cells adjacent to stars as X (row 5, column 3).
48. Row completion: 1 star needed, 1 candidate (row 5, column 4).
49. Mark 3 cells adjacent to stars as X (row 4, column 3).
50. Region completion: 1 star needed, 1 candidate (row 7, column 4).
51. Mark 1 cell adjacent to stars as X (row 8, column 4).
52. Region completion: 1 star needed, 1 candidate (row 4, column 2).
53. Row completion: 1 star needed, 1 candidate (row 8, column 1).
54. Mark 1 cell adjacent to stars as X (row 9, column 1).
55. Column 1 complete: Mark 1 remaining cell as X (row 10, column 1).
56. Column 2 complete: Mark 1 remaining cell as X (row 10, column 2).
57. Region completion: 1 star needed, 1 candidate (row 9, column 3).
58. Mark 2 cells adjacent to stars as X (row 9, column 4).
59. Region completion: 1 star needed, 1 candidate (row 10, column 5).
60. Solved! Every row, column, and region has its two stars, none touching.