Expert Star Battle answer — October 8, 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 5).
3. Clump analysis (Region 5): candidate clumps can only just supply the remaining stars (row 3, column 7).
4. Lookahead: Placing star here leads to contradiction - columns 1-4 must hold 8 stars but the regions there could only supply 7 (row 8, column 3).
5. Lookahead: Placing star here leads to contradiction - row 10 can only hold 2 stars but the regions there would be forced to place 3 (row 8, column 8).
6. Lookahead: Placing star here leads to contradiction - columns 1-3 must hold 6 stars but the regions there could only supply 5 (row 10, column 4).
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 9, column 2).
8. Triple analysis (Column 2 + Column 3 + Region 1): every legal combination of their stars rules these cells out (row 2, column 4).
9. Deep lookahead: Placing star here leads to contradiction - stars at R7C10 and R8C10 would touch (row 4, column 9).
10. Deep lookahead: Placing star here leads to contradiction - stars at R4C8 and R5C8 would touch (row 4, column 6).
11. Deep lookahead: Placing star here leads to contradiction - Row 8 would only have room for 0 of the 1 star it still needs (row 2, column 6).
12. Deep lookahead: Placing star here leads to contradiction - stars at R6C6 and R7C6 would touch (row 5, column 3).
13. Deep lookahead: Placing star here leads to contradiction - Column 7 would end up with more than 2 stars (row 5, column 8).
14. Deep lookahead: Placing star here leads to contradiction - column 9 must hold 2 stars but the regions there could only supply 1 (row 3, column 6).
15. Composite container (columns 1-6): Regions 1, 6, 8, 9 and 10 are confined here, so the leftover cells owe exactly 2 of the band's 12 stars - a star on these cells would crowd them out (row 6, column 5).
16. Clump analysis (Region 4): candidate clumps can only just supply the remaining stars (row 9, column 10).
17. Clump analysis (Region 6): candidate clumps can only just supply the remaining stars (row 6, column 3).
18. Crowding (Region 10): a star here would leave too little room for its 2 remaining stars (row 8, column 4).
19. Clump analysis (Row 8): candidate clumps can only just supply the remaining stars (row 7, column 1).
20. Squeeze (columns 6-7): each clump in the band must supply its full share of stars (row 7, column 6).
21. Lookahead: Placing star here leads to contradiction - Region 2 would end up with more than 2 stars (row 7, column 8).
22. Two last candidates (row 7): Eliminate 1 cell adjacent to both (row 6, column 4).
23. Three candidates with two adjacent: Isolated candidate must hold a star (row 5, column 6).
24. Mark 3 cells adjacent to stars as X (row 4, column 5).
25. Region completion: 1 star needed, 1 candidate (row 5, column 4).
26. Mark 1 cell adjacent to stars as X (row 4, column 3).
27. Row 5 complete: Mark 4 remaining cells as X (row 5, column 1).
28. Column 6 complete: Mark 3 remaining cells as X (row 1, column 6).
29. Three candidates with two adjacent: Isolated candidate must hold a star (row 6, column 8).
30. Mark 1 cell adjacent to stars as X (row 6, column 9).
31. Two-option rule: Cell adjacent to both candidates (row 3, column 9).
32. Clump analysis (Column 7): candidate clumps can only just supply the remaining stars (row 1, column 8).
33. Clump analysis (Region 3): candidate clumps can only just supply the remaining stars (row 1, column 9).
34. Clump analysis (Region 7): candidate clumps can only just supply the remaining stars (row 1, column 4).
35. Generalized counting (columns 10-10): region star limits exclude these cells (row 10, column 10).
36. Composite container (rows 3-10): Regions 1, 2, 4, 5, 9 and 10 are confined here, so the leftover cells owe exactly 2 of the band's 16 stars - a star on these cells would crowd them out (row 3, column 2).
37. Composite container (columns 7-9): Regions 4 and 5 are confined here, so the leftover cells owe exactly 2 of the band's 6 stars - a star on these cells would crowd them out (row 1, column 10).
38. Region completion: 2 stars needed, 2 candidates (row 2, column 9).
39. Region completion: 1 star needed, 1 candidate (row 4, column 10).
40. Region completion: 1 star needed, 1 candidate (row 4, column 8).
41. Row 4 complete: Mark 1 remaining cell as X (row 4, column 1).
42. 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).
43. Lookahead: Placing star here leads to contradiction - Region 10 would only have room for 0 of the 1 star it still needs (row 9, column 4).
44. Column completion: 1 star needed, 1 candidate (row 7, column 4).
45. Mark 1 cell adjacent to stars as X (row 7, column 3).
46. Generalized counting (rows 9-9): region star limits exclude these cells (row 10, column 5).
47. Composite container (rows 8-9): Region 10 is confined here, so the leftover cells owe exactly 3 of the band's 4 stars - a star on these cells would crowd them out (row 10, column 7).
48. Clump analysis (Column 7): each clump must supply its full share of stars (row 9, column 7).
49. Lookahead: This cell must be a star - eliminating it leads to contradiction (Region 1 would end up with more than 2 stars) (row 3, column 3).
50. Mark 1 cell adjacent to stars as X (row 2, column 3).
51. Generalized counting (rows 1-2): region star limits exclude these cells (row 3, column 1).
52. Row completion: 1 star needed, 1 candidate (row 3, column 5).
53. Mark 1 cell adjacent to stars as X (row 2, column 5).
54. Three candidates with two adjacent: Isolated candidate must hold a star (row 1, column 5).
55. Column 5 complete: Mark 1 remaining cell as X (row 9, column 5).
56. Region completion: 1 star needed, 1 candidate (row 9, column 3).
57. Mark 3 cells adjacent to stars as X (row 8, column 2).
58. Region completion: 2 stars needed, 2 candidates (row 8, column 1).
59. Region completion: 1 star needed, 1 candidate (row 10, column 1).
60. Row completion: 1 star needed, 1 candidate (row 10, column 9).
61. Region complete: Mark 1 remaining cell as X (row 8, column 9).
62. Row completion: 1 star needed, 1 candidate (row 8, column 10).
63. Region complete: Mark 1 remaining cell as X (row 6, column 10).
64. Column 1 complete: Mark 3 remaining cells as X (row 1, column 1).
65. Region completion: 1 star needed, 1 candidate (row 6, column 2).
66. Row completion: 1 star needed, 1 candidate (row 2, column 7).
67. Mark 1 cell adjacent to stars as X (row 1, column 7).
68. Column completion: 1 star needed, 1 candidate (row 1, column 2).
69. Mark 1 cell adjacent to stars as X (row 1, column 3).
70. Solved! Every row, column, and region has its two stars, none touching.