Hard Star Battle answer — April 3, 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 5, column 1).
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 5, column 7).
4. 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 7).
5. Three candidates with two adjacent: Isolated candidate must hold a star (row 5, column 8).
6. Mark 6 cells adjacent to stars as X (row 4, column 7).
7. Two-option rule: Cell adjacent to both candidates (row 5, column 5).
8. Two-option rule: Cell adjacent to both candidates (row 6, column 5).
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 8, column 2).
10. Clump analysis (Region 2): candidate clumps can only just supply the remaining stars (row 2, column 6).
11. Clump analysis (Region 3): candidate clumps can only just supply the remaining stars (row 3, column 1).
12. 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).
13. Clump analysis (Region 5): candidate clumps can only just supply the remaining stars (row 4, column 2).
14. Three candidates with two adjacent: Isolated candidate must hold a star (row 4, column 1).
15. Clump analysis (Column 2): candidate clumps can only just supply the remaining stars (row 1, column 1).
16. Region completion: 1 star needed, 1 candidate (row 6, column 2).
17. Mark 3 cells adjacent to stars as X (row 5, column 3).
18. Region completion: 2 stars needed, 2 candidates (row 4, column 3).
19. Mark 2 cells adjacent to stars as X (row 3, column 3).
20. Region completion: 1 star needed, 1 candidate (row 6, column 4).
21. Mark 1 cell adjacent to stars as X (row 7, column 5).
22. Row 4 complete: Mark 2 remaining cells as X (row 4, column 5).
23. Row completion: 1 star needed, 1 candidate (row 5, column 6).
24. Mark 1 cell adjacent to stars as X (row 6, column 6).
25. Two last candidates (column 3): Eliminate 2 cells adjacent to both (row 8, column 4).
26. Two last candidates (column 4): Eliminate 2 cells adjacent to both (row 1, column 5).
27. Clump analysis (Row 7): candidate clumps can only just supply the remaining stars (row 8, column 6).
28. Clump analysis (Column 5): candidate clumps can only just supply the remaining stars (row 9, column 6).
29. Clump analysis (Column 5): each clump must supply its full share of stars (row 3, column 5).
30. Mark 2 cells adjacent to stars as X (row 2, column 4).
31. Column completion: 1 star needed, 1 candidate (row 1, column 4).
32. Clump analysis (Column 2): candidate clumps can only just supply the remaining stars (row 1, column 6).
33. Column completion: 1 star needed, 1 candidate (row 7, column 6).
34. Mark 2 cells adjacent to stars as X (row 7, column 7).
35. Row completion: 2 stars needed, 2 candidates (row 8, column 1).
36. Mark 1 cell adjacent to stars as X (row 9, column 1).
37. Row completion: 1 star needed, 1 candidate (row 8, column 3).
38. Mark 1 cell adjacent to stars as X (row 9, column 3).
39. Column completion: 1 star needed, 1 candidate (row 9, column 5).
40. Clump analysis (Region 2): candidate clumps can only just supply the remaining stars (row 1, column 2).
41. Region completion: 1 star needed, 1 candidate (row 2, column 2).
42. Two last candidates (row 2): Eliminate 2 cells adjacent to both (row 1, column 8).
43. Clump analysis (Region 7): candidate clumps can only just supply the remaining stars (row 9, column 9).
44. Region completion: 1 star needed, 1 candidate (row 7, column 9).
45. Mark 1 cell adjacent to stars as X (row 7, column 8).
46. Column completion: 1 star needed, 1 candidate (row 9, column 8).
47. Mark 1 cell adjacent to stars as X (row 9, column 7).
48. Three candidates in a column: Middle cell can't hold a star (row 2, column 7).
49. Row completion: 1 star needed, 1 candidate (row 2, column 9).
50. Mark 2 cells adjacent to stars as X (row 1, column 9).
51. Region completion: 2 stars needed, 2 candidates (row 1, column 7).
52. Region completion: 1 star needed, 1 candidate (row 3, column 7).
53. Solved! Every row, column, and region has its two stars, none touching.