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