Expert Star Battle answer — July 4, 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 8, 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 2, column 2).
4. Clump analysis (Region 5): candidate clumps can only just supply the remaining stars (row 9, column 9).
5. Clump analysis (Region 6): candidate clumps can only just supply the remaining stars (row 7, column 2).
6. Crowding (Region 9): a star here would leave too little room for its 2 remaining stars (row 2, column 1).
7. Clump analysis (Region 10): candidate clumps can only just supply the remaining stars (row 5, column 3).
8. Triple analysis (Region 9 + Region 1 + Row 1): every legal combination of their stars rules these cells out (row 4, column 3).
9. Triple analysis (Region 9 + Region 10 + Column 1): every legal combination of their stars rules these cells out (row 5, column 1).
10. Triple analysis (Region 9 + Region 10 + Column 2): every legal combination of their stars rules these cells out (row 1, column 2).
11. Deep lookahead: Placing star here leads to contradiction - stars at R5C6 and R6C5 would touch (row 1, column 4).
12. Deep lookahead: Placing star here leads to contradiction - Region 10 would only have room for 1 of the 2 stars it still needs (row 1, column 5).
13. Deep lookahead: Placing star here leads to contradiction - stars at R5C6 and R6C5 would touch (row 2, column 4).
14. Triple analysis (Region 9 + Region 10 + Region 1): every legal combination of their stars rules these cells out (row 1, column 8).
15. Triple analysis (Region 10 + Region 1 + Row 3): every legal combination of their stars rules these cells out (row 3, column 6).
16. Deep lookahead: Placing star here leads to contradiction - rows 1-2 can only hold 4 stars but the regions there would be forced to place 5 (row 1, column 6).
17. Deep lookahead: Placing star here leads to contradiction - Region 2 would only have room for 0 of the 1 star it still needs (row 2, column 6).
18. Joint analysis (Row 2 + Row 3): every legal combination of their stars rules these cells out (row 4, column 2).
19. Joint analysis (Region 1 + Row 2): every legal combination of their stars rules these cells out (row 3, column 4).
20. Joint analysis (Region 10 + Column 2): every legal combination of their stars rules these cells out (row 6, column 1).
21. Joint analysis (Region 6 + Column 4): every legal combination of their stars rules these cells out (row 9, column 3).
22. Quad analysis (Region 10 + Column 4 + Region 2 + Row 5): every legal combination of their stars rules these cells out (row 7, column 3).
23. Deep lookahead: Placing star here leads to contradiction - Row 9 would only have room for 0 of the 1 star it still needs (row 1, column 1).
24. Region completion: 2 stars needed, 2 candidates (row 1, column 3).
25. Region completion: 1 star needed, 1 candidate (row 3, column 2).
26. Mark 3 cells adjacent to stars as X (row 3, column 1).
27. Region completion: 2 stars needed, 2 candidates (row 4, column 4).
28. Mark 4 cells adjacent to stars as X (row 3, column 5).
29. Region completion: 2 stars needed, 2 candidates (row 1, column 7).
30. Mark 2 cells adjacent to stars as X (row 2, column 7).
31. Region completion: 1 star needed, 1 candidate (row 2, column 5).
32. Region completion: 1 star needed, 1 candidate (row 5, column 2).
33. Mark 1 cell adjacent to stars as X (row 6, column 2).
34. Column 2 complete: Mark 2 remaining cells as X (row 9, column 2).
35. Three candidates with two adjacent: Isolated candidate must hold a star (row 8, column 3).
36. Mark 3 cells adjacent to stars as X (row 7, column 4).
37. Column 3 complete: Mark 1 remaining cell as X (row 10, column 3).
38. Three candidates with two adjacent: Isolated candidate must hold a star (row 6, column 4).
39. Mark 2 cells adjacent to stars as X (row 6, column 5).
40. Region completion: 1 star needed, 1 candidate (row 5, column 6).
41. Mark 5 cells adjacent to stars as X (row 4, column 6).
42. Row 5 complete: Mark 3 remaining cells as X (row 5, column 8).
43. Column 4 complete: Mark 1 remaining cell as X (row 10, column 4).
44. Two last candidates (row 2): Eliminate 2 cells adjacent to both (row 3, column 9).
45. Two last candidates (row 3): Eliminate 1 cell adjacent to both (row 4, column 8).
46. Three candidates with two adjacent: Isolated candidate must hold a star (row 6, column 8).
47. Mark 4 cells adjacent to stars as X (row 6, column 9).
48. Row 6 complete: Mark 1 remaining cell as X (row 6, column 10).
49. Clump analysis (Column 5): candidate clumps can only just supply the remaining stars (row 9, column 6).
50. Clump analysis (Region 8): candidate clumps can only just supply the remaining stars (row 8, column 6).
51. Region completion: 1 star needed, 1 candidate (row 7, column 1).
52. Row constraint forcing: Row 8 can only take 1 star, region needs 2 (row 7, column 6).
53. Mark 2 cells adjacent to stars as X (row 8, column 5).
54. Row 7 complete: Mark 1 remaining cell as X (row 7, column 10).
55. Column 6 complete: Mark 1 remaining cell as X (row 10, column 6).
56. 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 9).
57. Three candidates with two adjacent: Isolated candidate must hold a star (row 10, column 8).
58. Mark 2 cells adjacent to stars as X (row 9, column 7).
59. Column completion: 1 star needed, 1 candidate (row 3, column 7).
60. Mark 1 cell adjacent to stars as X (row 3, column 8).
61. Region completion: 1 star needed, 1 candidate (row 4, column 9).
62. Mark 1 cell adjacent to stars as X (row 4, column 10).
63. Column 8 complete: Mark 1 remaining cell as X (row 8, column 8).
64. Region completion: 1 star needed, 1 candidate (row 8, column 9).
65. Mark 1 cell adjacent to stars as X (row 9, column 10).
66. Region completion: 1 star needed, 1 candidate (row 10, column 10).
67. Row completion: 2 stars needed, 2 candidates (row 9, column 1).
68. Mark 1 cell adjacent to stars as X (row 10, column 1).
69. Row completion: 1 star needed, 1 candidate (row 9, column 5).
70. Mark 1 cell adjacent to stars as X (row 10, column 5).
71. Column 9 complete: Mark 1 remaining cell as X (row 2, column 9).
72. Region completion: 1 star needed, 1 candidate (row 2, column 10).
73. Solved! Every row, column, and region has its two stars, none touching.