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