Expert Star Battle answer — October 15, 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. Clump analysis (Region 5): candidate clumps can only just supply the remaining stars (row 10, column 1).
3. Clump analysis (Region 8): candidate clumps can only just supply the remaining stars (row 7, column 4).
4. Clump analysis (Region 10): candidate clumps can only just supply the remaining stars (row 5, column 7).
5. Generalized counting (rows 6-9): region star limits exclude these cells (row 6, column 10).
6. Composite container (rows 1-5): Regions 1, 3, 4 and 9 are confined here, so the leftover cells owe exactly 2 of the band's 10 stars - a star on these cells would crowd them out (row 4, column 2).
7. Clump analysis (Region 8): candidate clumps can only just supply the remaining stars (row 8, column 4).
8. Lookahead: Placing star here leads to contradiction - rows 1-4 must hold 8 stars but the regions there could only supply 7 (row 3, column 6).
9. Lookahead: Placing star here leads to contradiction - row 9 can only hold 2 stars but the regions there would be forced to place 3 (row 9, column 8).
10. Joint analysis (Region 3 + Region 1): every legal combination of their stars rules these cells out (row 2, column 9).
11. Joint analysis (Region 8 + Region 7): every legal combination of their stars rules these cells out (row 8, column 2).
12. Triple analysis (Region 3 + Region 1 + Column 10): every legal combination of their stars rules these cells out (row 2, column 8).
13. Deep lookahead: Placing star here leads to contradiction - stars at R9C2 and R9C3 would touch (row 2, column 6).
14. Deep lookahead: Placing star here leads to contradiction - stars at R5C3 and R6C4 would touch (row 3, column 5).
15. Deep lookahead: Placing star here leads to contradiction - Region 4 would end up with more than 2 stars (row 5, column 1).
16. Deep lookahead: Placing star here leads to contradiction - Region 4 would end up with more than 2 stars (row 5, column 4).
17. Composite container (rows 1-4): Regions 1, 4 and 9 are confined here, so the leftover cells owe exactly 2 of the band's 8 stars - a star on these cells would crowd them out (row 3, column 9).
18. Deep lookahead: Placing star here leads to contradiction - stars at R9C3 and R9C4 would touch (row 2, column 7).
19. Deep lookahead: Placing star here leads to contradiction - Region 8 would end up with more than 2 stars (row 1, column 2).
20. Deep lookahead: Placing star here leads to contradiction - Region 8 would end up with more than 2 stars (row 3, column 2).
21. Joint analysis (Column 2 + Column 1): every legal combination of their stars rules these cells out (row 8, column 1).
22. Triple analysis (Column 2 + Region 9 + Column 3): every legal combination of their stars rules these cells out (row 2, column 4).
23. Quad analysis (Column 2 + Region 6 + Region 9 + Column 3): every legal combination of their stars rules these cells out (row 9, column 1).
24. Deep lookahead: Placing star here leads to contradiction - Region 3 would only have room for 1 of the 2 stars it still needs (row 7, column 5).
25. Deep lookahead: Placing star here leads to contradiction - Column 7 would end up with more than 2 stars (row 6, column 9).
26. 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).
27. Composite container (rows 1-8): Regions 1, 3, 4, 6, 8, 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 7, column 7).
28. Composite container (columns 1-7): Regions 4, 6, 7, 8 and 9 are confined here, so the leftover cells owe exactly 4 of the band's 14 stars - a star on these cells would crowd them out (row 9, column 5).
29. Deep lookahead: Placing star here leads to contradiction - Region 4 would end up with more than 2 stars (row 8, column 6).
30. Squeeze (rows 8-9): the band's clumps can only just fit its stars (row 7, column 8).
31. Composite container (columns 1-7): Regions 4, 6, 7, 8 and 9 are confined here, so the leftover cells owe exactly 4 of the band's 14 stars - a star on these cells would crowd them out (row 9, column 4).
32. Three candidates with two adjacent: Isolated candidate must hold a star (row 8, column 7).
33. Mark 1 cell adjacent to stars as X (row 8, column 8).
34. 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).
35. Row completion: 1 star needed, 1 candidate (row 8, column 5).
36. Clump analysis (Row 9): candidate clumps can only just supply the remaining stars (row 10, column 9).
37. Generalized counting (columns 1-5): region star limits exclude these cells (row 1, column 6).
38. Lookahead: Placing star here leads to contradiction - columns 1-3 must hold 6 stars but the regions there could only supply 5 (row 4, column 4).
39. Joint analysis (Column 4 + Column 3): every legal combination of their stars rules these cells out (row 2, column 3).
40. Triple analysis (Column 4 + Region 4 + Column 3): every legal combination of their stars rules these cells out (row 2, column 5).
41. Clump analysis (Row 2): candidate clumps can only just supply the remaining stars (row 1, column 1).
42. Clump analysis (Row 2): each clump must supply its full share of stars (row 2, column 10).
43. Mark 3 cells adjacent to stars as X (row 1, column 9).
44. Clump analysis (Row 3): candidate clumps can only just supply the remaining stars (row 4, column 8).
45. Squeeze (columns 1-2): the band's clumps can only just fit its stars (row 9, column 3).
46. Region completion: 1 star needed, 1 candidate (row 9, column 2).
47. Composite container (rows 1-4): Regions 1, 4 and 9 are confined here, so the leftover cells owe exactly 2 of the band's 8 stars - a star on these cells would crowd them out (row 5, column 9).
48. Crowding (Row 5): a star here would leave too little room for its 2 remaining stars (row 6, column 7).
49. Squeeze (columns 6-7): the band's clumps can only just fit its stars (row 6, column 5).
50. Triple analysis (Column 9 + Region 3 + Region 10): every legal combination of their stars rules these cells out (row 9, column 10).
51. Row completion: 1 star needed, 1 candidate (row 9, column 9).
52. Lookahead: This cell must be a star - eliminating it leads to contradiction (Column 7 would end up with more than 2 stars) (row 1, column 5).
53. Mark 1 cell adjacent to stars as X (row 1, column 4).
54. Column 5 complete: Mark 1 remaining cell as X (row 10, column 5).
55. Three candidates with two adjacent: Isolated candidate must hold a star (row 10, column 4).
56. Lookahead: Placing star here leads to contradiction - Region 4 would end up with more than 2 stars (row 6, column 4).
57. Region completion: 1 star needed, 1 candidate (row 7, column 3).
58. Mark 1 cell adjacent to stars as X (row 7, column 2).
59. Column completion: 1 star needed, 1 candidate (row 3, column 4).
60. Mark 1 cell adjacent to stars as X (row 3, column 3).
61. Clump analysis (Region 2): candidate clumps can only just supply the remaining stars (row 7, column 1).
62. Three candidates with two adjacent: Isolated candidate must hold a star (row 6, column 1).
63. Mark 1 cell adjacent to stars as X (row 5, column 2).
64. Region completion: 1 star needed, 1 candidate (row 5, column 3).
65. Column completion: 1 star needed, 1 candidate (row 2, column 2).
66. Mark 2 cells adjacent to stars as X (row 1, column 3).
67. Region completion: 1 star needed, 1 candidate (row 4, column 1).
68. Row completion: 1 star needed, 1 candidate (row 1, column 8).
69. Region complete: Mark 1 remaining cell as X (row 3, column 8).
70. Row completion: 1 star needed, 1 candidate (row 3, column 7).
71. Mark 1 cell adjacent to stars as X (row 4, column 6).
72. Column 7 complete: Mark 1 remaining cell as X (row 10, column 7).
73. Region completion: 1 star needed, 1 candidate (row 10, column 6).
74. Three candidates with two adjacent: Isolated candidate must hold a star (row 6, column 8).
75. Mark 2 cells adjacent to stars as X (row 5, column 8).
76. Region completion: 1 star needed, 1 candidate (row 7, column 10).
77. Row completion: 1 star needed, 1 candidate (row 5, column 6).
78. Mark 1 cell adjacent to stars as X (row 6, column 6).
79. Column completion: 1 star needed, 1 candidate (row 4, column 9).
80. Mark 1 cell adjacent to stars as X (row 4, column 10).
81. Solved! Every row, column, and region has its two stars, none touching.