Hard Star Battle answer — November 23, 2025

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 2, column 5).
3. 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 1).
4. Three candidates with two adjacent: Isolated candidate must hold a star (row 8, column 1).
5. Mark 4 cells adjacent to stars as X (row 7, column 2).
6. Two-option rule: Cell adjacent to both candidates (row 5, column 1).
7. Two-option rule: Cell adjacent to both candidates (row 5, column 2).
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 9, column 4).
9. Three candidates with two adjacent: Isolated candidate must hold a star (row 9, column 3).
10. Mark 2 cells adjacent to stars as X (row 8, column 3).
11. Two-option rule: Cell adjacent to both candidates (row 8, column 6).
12. Two-option rule: Cell adjacent to both candidates (row 9, column 6).
13. Blocking rule: a star here would touch every other open cell in its region, leaving no room for the region's second star (row 5, column 5).
14. Three candidates with two adjacent: Isolated candidate must hold a star (row 6, column 4).
15. Mark 7 cells adjacent to stars as X (row 5, column 3).
16. Region completion: 1 star needed, 1 candidate (row 5, column 6).
17. Mark 6 cells adjacent to stars as X (row 4, column 5).
18. Blocking rule: a star here would touch every other open cell in its region, leaving no room for the region's second star (row 8, column 8).
19. Blocking rule: a star here would touch every other open cell in its region, leaving no room for the region's second star (row 8, column 9).
20. Three candidates with two adjacent: Isolated candidate must hold a star (row 7, column 9).
21. Mark 3 cells adjacent to stars as X (row 6, column 8).
22. Two last candidates (row 5): Eliminate 2 cells adjacent to both (row 4, column 8).
23. Two last candidates (row 7): Eliminate 1 cell adjacent to both (row 8, column 7).
24. Row completion: 1 star needed, 1 candidate (row 8, column 5).
25. Mark 2 cells adjacent to stars as X (row 7, column 6).
26. Row completion: 1 star needed, 1 candidate (row 7, column 7).
27. Two last candidates (column 5): Eliminate 2 cells adjacent to both (row 2, column 4).
28. Two last candidates (column 6): Eliminate 1 cell adjacent to both (row 2, column 7).
29. Clump analysis (Row 4): candidate clumps can only just supply the remaining stars (row 3, column 1).
30. Clump analysis (Row 3): candidate clumps can only just supply the remaining stars (row 2, column 8).
31. Clump analysis (Region 2): candidate clumps can only just supply the remaining stars (row 1, column 2).
32. Region completion: 1 star needed, 1 candidate (row 6, column 2).
33. Clump analysis (Region 2): each clump must supply its full share of stars (row 4, column 1).
34. Mark 1 cell adjacent to stars as X (row 4, column 2).
35. Column 1 complete: Mark 2 remaining cells as X (row 1, column 1).
36. Region completion: 1 star needed, 1 candidate (row 2, column 2).
37. Mark 2 cells adjacent to stars as X (row 1, column 3).
38. Row completion: 1 star needed, 1 candidate (row 2, column 9).
39. Mark 4 cells adjacent to stars as X (row 1, column 8).
40. Column completion: 1 star needed, 1 candidate (row 4, column 3).
41. Mark 1 cell adjacent to stars as X (row 4, column 4).
42. Region completion: 1 star needed, 1 candidate (row 1, column 4).
43. Mark 1 cell adjacent to stars as X (row 1, column 5).
44. Column completion: 1 star needed, 1 candidate (row 3, column 5).
45. Mark 1 cell adjacent to stars as X (row 3, column 6).
46. Region completion: 1 star needed, 1 candidate (row 1, column 6).
47. Mark 1 cell adjacent to stars as X (row 1, column 7).
48. Row completion: 1 star needed, 1 candidate (row 3, column 7).
49. Region complete: Mark 1 remaining cell as X (row 9, column 7).
50. Column completion: 2 stars needed, 2 candidates (row 5, column 8).
51. Mark 1 cell adjacent to stars as X (row 5, column 9).
52. Column completion: 1 star needed, 1 candidate (row 9, column 8).
53. Mark 1 cell adjacent to stars as X (row 9, column 9).
54. Solved! Every row, column, and region has its two stars, none touching.