Expert Star Battle answer — September 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: 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).
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 10, column 2).
4. Three candidates with two adjacent: Isolated candidate must hold a star (row 9, column 3).
5. Mark 6 cells adjacent to stars as X (row 8, column 2).
6. Blocking rule: a star here would touch every other open cell in its region, leaving no room for the region's second star (row 6, column 9).
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 6, column 10).
8. Three candidates with two adjacent: Isolated candidate must hold a star (row 7, column 10).
9. Mark 3 cells adjacent to stars as X (row 7, column 9).
10. Two-option rule: Cell adjacent to both candidates (row 4, column 9).
11. Two-option rule: Cell adjacent to both candidates (row 4, column 10).
12. Clump analysis (Region 8): candidate clumps can only just supply the remaining stars (row 2, column 7).
13. Lookahead: Placing star here leads to contradiction - columns 8-10 must hold 6 stars but the regions there could only supply 5 (row 6, column 7).
14. Generalized counting (rows 9-10): region star limits exclude these cells (row 9, column 5).
15. Composite container (rows 1-8): Regions 3, 4, 5, 7, 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 6, column 3).
16. Clump analysis (Region 4): candidate clumps can only just supply the remaining stars (row 4, column 3).
17. Crowding (Row 6): a star here would leave too little room for its 2 remaining stars (row 5, column 7).
18. Crowding (Row 8): a star here would leave too little room for its 2 remaining stars (row 9, column 7).
19. Composite container (rows 1-8): Regions 3, 4, 5, 7, 8, 9 and 10 are confined here, so the leftover cells owe exactly 2 of the band's 16 stars - impossible without stars on these cells (row 7, column 4).
20. Row 7 complete: Mark 4 remaining cells as X (row 7, column 1).
21. Composite container (rows 1-8): Regions 3, 4, 5, 7, 8, 9 and 10 are confined here, so the leftover cells owe exactly 1 of the band's 16 stars - a star on these cells would crowd them out (row 9, column 8).
22. Composite container (columns 5-10): Regions 1, 2, 5, 7 and 9 are confined here, so the leftover cells owe exactly 3 of the band's 12 stars - a star on these cells would crowd them out (row 2, column 6).
23. Composite container (columns 4-10): Regions 1, 2, 5, 7, 8 and 9 are confined here, so the leftover cells owe exactly 2 of the band's 14 stars - a star on these cells would crowd them out (row 2, column 5).
24. Composite container (columns 5-7): Region 2 is confined here, so the leftover cells owe exactly 5 of the band's 6 stars - a star on these cells would crowd them out (row 2, column 4).
25. Clump analysis (Region 3): candidate clumps can only just supply the remaining stars (row 4, column 4).
26. Clump analysis (Row 4): candidate clumps can only just supply the remaining stars (row 3, column 1).
27. Crowding (Column 2): a star here would leave too little room for its 2 remaining stars (row 5, column 3).
28. Three candidates with two adjacent: Isolated candidate must hold a star (row 4, column 2).
29. Mark 2 cells adjacent to stars as X (row 3, column 3).
30. Two last candidates (column 3): Eliminate 3 cells adjacent to both (row 1, column 2).
31. Column completion: 1 star needed, 1 candidate (row 6, column 2).
32. Mark 1 cell adjacent to stars as X (row 6, column 1).
33. Generalized counting (rows 5-5): region star limits exclude these cells (row 5, column 6).
34. Row constraint forcing: Row 6 can only take 1 star, region needs 2 (row 8, column 6).
35. Mark 2 cells adjacent to stars as X (row 8, column 7).
36. 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 9).
37. Generalized counting (rows 8-10): region star limits exclude these cells (row 8, column 1).
38. Row completion: 1 star needed, 1 candidate (row 8, column 8).
39. Composite container (columns 5-7): Regions 2 and 8 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 3, column 6).
40. Three candidates with two adjacent: Isolated candidate must hold a star (row 1, column 7).
41. Mark 3 cells adjacent to stars as X (row 1, column 6).
42. Region completion: 1 star needed, 1 candidate (row 1, column 5).
43. Row 1 complete: Mark 4 remaining cells as X (row 1, column 1).
44. Region completion: 1 star needed, 1 candidate (row 2, column 1).
45. Column completion: 1 star needed, 1 candidate (row 2, column 3).
46. Mark 1 cell adjacent to stars as X (row 3, column 4).
47. Region completion: 1 star needed, 1 candidate (row 3, column 5).
48. Row 2 complete: Mark 2 remaining cells as X (row 2, column 9).
49. Column completion: 1 star needed, 1 candidate (row 5, column 4).
50. Mark 1 cell adjacent to stars as X (row 5, column 5).
51. Column 5 complete: Mark 1 remaining cell as X (row 10, column 5).
52. Crowding (Column 9): a star here would leave too little room for its 2 remaining stars (row 4, column 8).
53. Row completion: 1 star needed, 1 candidate (row 4, column 7).
54. Column 7 complete: Mark 1 remaining cell as X (row 10, column 7).
55. Region completion: 1 star needed, 1 candidate (row 10, column 6).
56. Column 6 complete: Mark 1 remaining cell as X (row 6, column 6).
57. Region completion: 1 star needed, 1 candidate (row 6, column 8).
58. Mark 1 cell adjacent to stars as X (row 5, column 9).
59. Region completion: 1 star needed, 1 candidate (row 5, column 10).
60. Column 8 complete: Mark 1 remaining cell as X (row 10, column 8).
61. Column completion: 2 stars needed, 2 candidates (row 3, column 9).
62. Mark 1 cell adjacent to stars as X (row 3, column 10).
63. Column completion: 1 star needed, 1 candidate (row 10, column 9).
64. Mark 2 cells adjacent to stars as X (row 9, column 10).
65. Row completion: 1 star needed, 1 candidate (row 9, column 1).
66. Mark 1 cell adjacent to stars as X (row 10, column 1).
67. Solved! Every row, column, and region has its two stars, none touching.