Expert Star Battle answer — September 27, 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: This position would block too many candidates (row 5, column 5).
3. Blocking rule: This position would block too many candidates (row 5, column 6).
4. Three candidates with two adjacent: Isolated candidate must hold a star (row 4, column 6).
5. Mark 6 cells adjacent to stars as X (row 3, column 5).
6. Two-option rule: Cell adjacent to both candidates (row 7, column 5).
7. Two-option rule: Cell adjacent to both candidates (row 7, column 6).
8. Clump analysis (Region 2): candidate clumps can only just supply the remaining stars (row 2, column 9).
9. Clump analysis (Region 6): candidate clumps can only just supply the remaining stars (row 7, column 3).
10. Clump analysis (Region 8): candidate clumps can only just supply the remaining stars (row 8, column 8).
11. Generalized counting (rows 9-10): region star limits exclude these cells (row 8, column 10).
12. Composite container (rows 9-10): Region 5 is confined here, so the leftover cells owe exactly 2 of the band's 4 stars - a star on these cells would crowd them out (row 10, column 4).
13. Joint analysis (Column 5 + Region 1): every legal combination of their stars rules these cells out (row 9, column 4).
14. Composite container (rows 9-10): Region 5 is confined here, so the leftover cells owe exactly 2 of the band's 4 stars - a star on these cells would crowd them out (row 9, column 2).
15. Joint analysis (Region 2 + Region 3): every legal combination of their stars rules these cells out (row 9, column 10).
16. Triple analysis (Column 2 + Column 1 + Region 4): every legal combination of their stars rules these cells out (row 5, column 3).
17. Deep lookahead: Placing star here leads to contradiction - columns 3-4 must hold 4 stars but the regions there could only supply 3 (row 2, column 3).
18. Deep lookahead: Placing star here leads to contradiction - rows 9-10 must hold 4 stars but the regions there could only supply 3 (row 2, column 5).
19. Composite container (columns 1-5): Regions 1, 4, 6 and 10 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 5, column 4).
20. Crowding (Row 5): a star here would leave too little room for its 2 remaining stars (row 4, column 9).
21. Deep lookahead: Placing star here leads to contradiction - Column 8 would only have room for 0 of the 1 star it still needs (row 2, column 8).
22. Deep lookahead: Placing star here leads to contradiction - Region 6 would only have room for 0 of the 1 star it still needs (row 4, column 2).
23. Generalized counting (columns 1-2): region star limits exclude these cells (row 6, column 3).
24. Clump analysis (Region 6): candidate clumps can only just supply the remaining stars (row 7, column 1).
25. Joint analysis (Column 3 + Column 4): every legal combination of their stars rules these cells out (row 8, column 5).
26. Triple analysis (Region 10 + Row 2 + Row 3): every legal combination of their stars rules these cells out (row 4, column 4).
27. Generalized counting (columns 3-4): region star limits exclude these cells (row 1, column 5).
28. Clump analysis (Column 5): candidate clumps can only just supply the remaining stars (row 9, column 6).
29. Region completion: 1 star needed, 1 candidate (row 6, column 5).
30. Mark 2 cells adjacent to stars as X (row 6, column 4).
31. Three candidates with two adjacent: Isolated candidate must hold a star (row 10, column 3).
32. Mark 1 cell adjacent to stars as X (row 9, column 3).
33. Region completion: 1 star needed, 1 candidate (row 8, column 4).
34. Mark 1 cell adjacent to stars as X (row 9, column 5).
35. Column completion: 1 star needed, 1 candidate (row 10, column 5).
36. Row 10 complete: Mark 4 remaining cells as X (row 10, column 1).
37. Clump analysis (Region 5): each clump must supply its full share of stars (row 9, column 1).
38. Mark 2 cells adjacent to stars as X (row 8, column 1).
39. Two-option rule: Cell adjacent to both candidates (row 6, column 1).
40. Squeeze (columns 6-7): the band's clumps can only just fit its stars (row 6, column 8).
41. Clump analysis (Region 8): candidate clumps can only just supply the remaining stars (row 7, column 10).
42. Squeeze (rows 7-8): the band's clumps can only just fit its stars (row 6, column 2).
43. Region completion: 1 star needed, 1 candidate (row 7, column 2).
44. Squeeze (rows 5-6): the band's clumps can only just fit its stars (row 4, column 1).
45. Composite container (columns 6-9): Regions 5, 8 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 4, column 8).
46. Joint analysis (Row 6 + Region 3): every legal combination of their stars rules these cells out (row 5, column 10).
47. Clump analysis (Region 2): candidate clumps can only just supply the remaining stars (row 1, column 9).
48. Composite container (rows 1-5): Regions 2, 4 and 10 are confined here, so the leftover cells owe exactly 3 of the band's 10 stars - a star on these cells would crowd them out (row 2, column 7).
49. Triple analysis (Row 6 + Row 5 + Column 9): every legal combination of their stars rules these cells out (row 4, column 10).
50. Row completion: 1 star needed, 1 candidate (row 4, column 3).
51. Mark 4 cells adjacent to stars as X (row 3, column 2).
52. Column 3 complete: Mark 1 remaining cells as X (row 1, column 3).
53. Blocking rule: This position would block too many candidates (row 2, column 10).
54. Three candidates with two adjacent: Isolated candidate must hold a star (row 1, column 10).
55. Two last candidates (column 2): Eliminate 2 cells adjacent to both (row 1, column 1).
56. Clump analysis (Row 5): candidate clumps can only just supply the remaining stars (row 3, column 1).
57. Column completion: 1 star needed, 1 candidate (row 5, column 1).
58. Three candidates in a row: Middle cell can't hold a star (row 3, column 9).
59. Region completion: 1 star needed, 1 candidate (row 3, column 10).
60. Row completion: 1 star needed, 1 candidate (row 3, column 8).
61. Column 10 complete: Mark 1 remaining cells as X (row 6, column 10).
62. Row completion: 1 star needed, 1 candidate (row 6, column 7).
63. Mark 2 cells adjacent to stars as X (row 5, column 8).
64. Region completion: 1 star needed, 1 candidate (row 5, column 9).
65. Row completion: 1 star needed, 1 candidate (row 7, column 9).
66. Mark 1 cell adjacent to stars as X (row 8, column 9).
67. Column 9 complete: Mark 1 remaining cells as X (row 9, column 9).
68. Two-option rule: Cell adjacent to both candidates (row 8, column 7).
69. Region completion: 1 star needed, 1 candidate (row 8, column 6).
70. Mark 1 cell adjacent to stars as X (row 9, column 7).
71. Region completion: 1 star needed, 1 candidate (row 9, column 8).
72. Column 6 complete: Mark 2 remaining cells as X (row 1, column 6).
73. Row completion: 2 stars needed, 2 candidates (row 2, column 2).
74. Mark 1 cell adjacent to stars as X (row 1, column 2).
75. Row completion: 1 star needed, 1 candidate (row 2, column 4).
76. Mark 1 cell adjacent to stars as X (row 1, column 4).
77. Column completion: 1 star needed, 1 candidate (row 1, column 7).
78. Mark 1 cell adjacent to stars as X (row 1, column 8).
79. Solved! Every row, column, and region has its two stars, none touching.