Expert Star Battle answer — October 2, 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 6, column 2).
3. Blocking rule: This position would block too many candidates (row 7, column 2).
4. Clump analysis (Region 1): candidate clumps can only just supply the remaining stars (row 9, column 8).
5. Clump analysis (Region 3): candidate clumps can only just supply the remaining stars (row 6, column 4).
6. Clump analysis (Region 4): candidate clumps can only just supply the remaining stars (row 8, column 9).
7. Clump analysis (Region 10): candidate clumps can only just supply the remaining stars (row 8, column 7).
8. Clump analysis (Region 1): candidate clumps can only just supply the remaining stars (row 10, column 5).
9. Blocking rule: This position would block too many candidates (row 9, column 9).
10. Three candidates with two adjacent: Isolated candidate must hold a star (row 8, column 8).
11. Mark 3 cells adjacent to stars as X (row 7, column 7).
12. Clump analysis (Region 4): candidate clumps can only just supply the remaining stars (row 5, column 9).
13. Generalized counting (columns 10-10): region star limits exclude these cells (row 1, column 10).
14. Lookahead: Placing star here leads to contradiction - column 1 can only hold 2 stars but the regions there would be forced to place 3 (row 1, column 1).
15. Lookahead: Placing star here leads to contradiction - column 10 can only hold 2 stars but the regions there would be forced to place 3 (row 5, column 10).
16. Blocking rule: This position would block too many candidates (row 7, column 10).
17. Three candidates with two adjacent: Isolated candidate must hold a star (row 8, column 10).
18. Mark 1 cell adjacent to stars as X (row 9, column 10).
19. Region completion: 1 star needed, 1 candidate (row 10, column 10).
20. Row 8 complete: Mark 6 remaining cells as X (row 8, column 1).
21. Column 10 complete: Mark 1 remaining cells as X (row 6, column 10).
22. Region completion: 1 star needed, 1 candidate (row 6, column 9).
23. Mark 2 cells adjacent to stars as X (row 5, column 8).
24. Clump analysis (Region 1): candidate clumps can only just supply the remaining stars (row 10, column 1).
25. Composite container (rows 1-7): Regions 2, 3, 5, 6, 8 and 9 are confined here, so the leftover cells owe exactly 1 of the band's 14 stars - a star on these cells would crowd them out (row 5, column 4).
26. Lookahead: Placing star here leads to contradiction - Region 1 would only have room for 0 of the 1 star it still needs (row 10, column 6).
27. Triple analysis (Column 4 + Region 2 + Region 6): every legal combination of their stars rules these cells out (row 2, column 5).
28. Deep lookahead: Placing star here leads to contradiction - stars at R5C1 and R5C2 would touch (row 1, column 3).
29. Quad analysis (Column 4 + Row 5 + Region 6 + Region 2): every legal combination of their stars rules these cells out (row 4, column 2).
30. Deep lookahead: Placing star here leads to contradiction - columns 2-3 must hold 4 stars but the regions there could only supply 3 (row 1, column 5).
31. Joint analysis (Column 2 + Region 6): every legal combination of their stars rules these cells out (row 2, column 3).
32. Triple analysis (Row 1 + Row 2 + Region 9): every legal combination of their stars rules these cells out (row 3, column 9).
33. Triple analysis (Region 6 + Region 5 + Row 3): every legal combination of their stars rules these cells out (row 2, column 2).
34. Generalized counting (columns 1-1): region star limits exclude these cells (row 9, column 1).
35. Composite container (columns 2-9): Regions 1, 5, 6, 7, 8 and 9 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 4, column 3).
36. Three candidates with two adjacent: Isolated candidate must hold a star (row 7, column 3).
37. Triple analysis (Column 8 + Row 2 + Row 3): every legal combination of their stars rules these cells out (row 1, column 8).
38. Quad analysis (Region 6 + Region 2 + Row 2 + Row 3): every legal combination of their stars rules these cells out (row 4, column 4).
39. Quad analysis (Region 5 + Column 5 + Column 6 + Region 8): every legal combination of their stars rules these cells out (row 2, column 7).
40. Triple analysis (Column 2 + Row 2 + Row 3): every legal combination of their stars rules these cells out (row 4, column 1).
41. Clump analysis (Row 4): candidate clumps can only just supply the remaining stars (row 3, column 6).
42. Joint analysis (Row 2 + Row 3): every legal combination of their stars rules these cells out (row 1, column 9).
43. Quad analysis (Row 4 + Column 6 + Column 5 + Region 8): every legal combination of their stars rules these cells out (row 1, column 7).
44. Deep lookahead: Placing star here leads to contradiction - Region 1 would only have room for 1 of the 2 stars it still needs (row 2, column 1).
45. Crowding (Row 2): a star here would leave too little room for its 2 remaining stars (row 3, column 5).
46. Squeeze (rows 1-2): each clump in the band must supply its full share of stars (row 1, column 2).
47. Joint analysis (Region 6 + Column 4): every legal combination of their stars rules these cells out (row 3, column 3).
48. Deep lookahead: Placing star here leads to contradiction - Column 9 would end up with more than 2 stars (row 1, column 6).
49. Row completion: 1 star needed, 1 candidate (row 1, column 4).
50. Mark 1 cell adjacent to stars as X (row 2, column 4).
51. Region complete: Mark 1 remaining cells as X (row 3, column 2).
52. Clump analysis (Row 2): each clump must supply its full share of stars (row 2, column 6).
53. Mark 1 cell adjacent to stars as X (row 3, column 7).
54. Row completion: 2 stars needed, 2 candidates (row 3, column 1).
55. Row completion: 1 star needed, 1 candidate (row 3, column 4).
56. Mark 1 cell adjacent to stars as X (row 4, column 5).
57. Column 4 complete: Mark 1 remaining cells as X (row 9, column 4).
58. Two-option rule: Cell adjacent to both candidates (row 5, column 7).
59. Clump analysis (Region 2): each clump must supply its full share of stars (row 5, column 5).
60. Mark 2 cells adjacent to stars as X (row 4, column 6).
61. Region completion: 1 star needed, 1 candidate (row 4, column 7).
62. Mark 1 cell adjacent to stars as X (row 4, column 8).
63. Row completion: 1 star needed, 1 candidate (row 4, column 9).
64. Region complete: Mark 1 remaining cells as X (row 2, column 9).
65. Row completion: 1 star needed, 1 candidate (row 2, column 8).
66. Column 8 complete: Mark 1 remaining cells as X (row 10, column 8).
67. Row completion: 1 star needed, 1 candidate (row 10, column 7).
68. Mark 1 cell adjacent to stars as X (row 9, column 6).
69. Region completion: 1 star needed, 1 candidate (row 9, column 5).
70. Column 5 complete: Mark 1 remaining cells as X (row 7, column 5).
71. Column completion: 1 star needed, 1 candidate (row 7, column 6).
72. Mark 1 cell adjacent to stars as X (row 6, column 7).
73. Row completion: 1 star needed, 1 candidate (row 6, column 1).
74. Mark 3 cells adjacent to stars as X (row 5, column 1).
75. Region completion: 1 star needed, 1 candidate (row 5, column 3).
76. Column completion: 1 star needed, 1 candidate (row 9, column 2).
77. Mark 1 cell adjacent to stars as X (row 9, column 3).
78. Solved! Every row, column, and region has its two stars, none touching.