Expert Star Battle answer — June 22, 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 2, column 1).
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. Three candidates with two adjacent: Isolated candidate must hold a star (row 3, column 1).
5. Mark 3 cells adjacent to stars as X (row 3, 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 2, column 8).
7. Clump analysis (Region 7): candidate clumps can only just supply the remaining stars (row 8, column 2).
8. Clump analysis (Region 10): candidate clumps can only just supply the remaining stars (row 3, column 7).
9. Lookahead: Placing star here leads to contradiction - row 1 can only hold 2 stars but the regions there would be forced to place 3 (row 1, column 7).
10. Lookahead: Placing star here leads to contradiction - row 1 can only hold 2 stars but the regions there would be forced to place 3 (row 1, column 10).
11. Lookahead: Placing star here leads to contradiction - rows 7-10 can only hold 8 stars but the regions there would be forced to place 9 (row 7, column 9).
12. Joint analysis (Region 10 + Row 3): every legal combination of their stars rules these cells out (row 3, column 6).
13. Joint analysis (Column 1 + Region 7): every legal combination of their stars rules these cells out (row 6, column 3).
14. Quad analysis (Region 5 + Region 1 + Region 8 + Row 10): every legal combination of their stars rules these cells out (row 5, column 4).
15. Deep lookahead: Placing star here leads to contradiction - row 1 can only hold 2 stars but the regions there would be forced to place 3 (row 1, column 6).
16. Deep lookahead: Placing star here leads to contradiction - stars at R6C9 and R7C8 would touch (row 4, column 7).
17. Clump analysis (Region 3): candidate clumps can only just supply the remaining stars (row 5, column 9).
18. Deep lookahead: Placing star here leads to contradiction - columns 8-9 must hold 4 stars but the regions there could only supply 3 (row 4, column 9).
19. Deep lookahead: Placing star here leads to contradiction - stars at R8C6 and R9C6 would touch (row 1, column 3).
20. Deep lookahead: Placing star here leads to contradiction - rows 1-3 can only hold 6 stars but the regions there would be forced to place 7 (row 5, column 7).
21. Deep lookahead: Placing star here leads to contradiction - columns 5-6 can only hold 4 stars but the regions there would be forced to place 5 (row 6, column 2).
22. Deep lookahead: Placing star here leads to contradiction - Column 3 would only have room for 1 of the 2 stars it still needs (row 6, column 8).
23. Deep lookahead: Placing star here leads to contradiction - columns 1-2 can only hold 4 stars but the regions there would be forced to place 5 (row 7, column 6).
24. Deep lookahead: Placing star here leads to contradiction - Row 6 would only have room for 0 of the 1 star it still needs (row 7, column 10).
25. Deep lookahead: Placing star here leads to contradiction - stars at R9C9 and R9C10 would touch (row 8, column 4).
26. Quad analysis (Column 2 + Region 5 + Region 1 + Region 7): every legal combination of their stars rules these cells out (row 1, column 1).
27. Region completion: 1 star needed, 1 candidate (row 1, column 2).
28. Mark 1 cell adjacent to stars as X (row 2, column 3).
29. Triple analysis (Column 2 + Region 5 + Region 7): every legal combination of their stars rules these cells out (row 10, column 1).
30. Clump analysis (Region 1): candidate clumps can only just supply the remaining stars (row 9, column 3).
31. Deep lookahead: Placing star here leads to contradiction - Column 7 would only have room for 0 of the 1 star it still needs (row 3, column 3).
32. Quad analysis (Region 5 + Column 3 + Region 1 + Row 10): every legal combination of their stars rules these cells out (row 10, column 7).
33. 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 6).
34. Clump analysis (Region 8): candidate clumps can only just supply the remaining stars (row 7, column 4).
35. Joint analysis (Region 5 + Column 3): every legal combination of their stars rules these cells out (row 7, column 2).
36. Deep lookahead: Placing star here leads to contradiction - Row 5 would only have room for 1 of the 2 stars it still needs (row 1, column 4).
37. Deep lookahead: Placing star here leads to contradiction - Region 8 would only have room for 1 of the 2 stars it still needs (row 3, column 5).
38. Deep lookahead: Placing star here leads to contradiction - Region 1 would only have room for 0 of the 1 star it still needs (row 3, column 9).
39. Deep lookahead: Placing star here leads to contradiction - Region 7 would only have room for 0 of the 1 star it still needs (row 4, column 3).
40. Triple analysis (Region 10 + Row 4 + Region 2): every legal combination of their stars rules these cells out (row 5, column 5).
41. Deep lookahead: Placing star here leads to contradiction - stars at R1C9 and R2C10 would touch (row 4, column 4).
42. Squeeze (columns 3-4): the band's clumps can only just fit its stars (row 2, column 5).
43. Deep lookahead: Placing star here leads to contradiction - Row 5 would only have room for 1 of the 2 stars it still needs (row 1, column 8).
44. Clump analysis (Region 10): candidate clumps can only just supply the remaining stars (row 2, column 10).
45. Deep lookahead: Placing star here leads to contradiction - Column 7 would only have room for 0 of the 1 star it still needs (row 2, column 6).
46. Clump analysis (Region 2): candidate clumps can only just supply the remaining stars (row 4, column 5).
47. Crowding (Row 2): a star here would leave too little room for its 2 remaining stars (row 3, column 8).
48. Three candidates with two adjacent: Isolated candidate must hold a star (row 2, column 7).
49. Deep lookahead: Placing star here leads to contradiction - Row 2 would only have room for 0 of the 1 star it still needs (row 5, column 1).
50. Squeeze (rows 4-5): the band's clumps can only just fit its stars (row 3, column 10).
51. Row completion: 1 star needed, 1 candidate (row 3, column 4).
52. Mark 1 cell adjacent to stars as X (row 2, column 4).
53. Row completion: 1 star needed, 1 candidate (row 2, column 9).
54. Mark 1 cell adjacent to stars as X (row 1, column 9).
55. Row completion: 1 star needed, 1 candidate (row 1, column 5).
56. Clump analysis (Region 8): candidate clumps can only just supply the remaining stars (row 6, column 5).
57. Generalized counting (columns 8-10): region star limits exclude these cells (row 6, column 6).
58. Two last candidates (column 7): Eliminate 3 cells adjacent to both (row 8, column 8).
59. Clump analysis (Column 6): each clump must supply its full share of stars (row 10, column 6).
60. Mark 1 cell adjacent to stars as X (row 9, column 7).
61. Column completion: 1 star needed, 1 candidate (row 8, column 7).
62. Mark 1 cell adjacent to stars as X (row 7, column 8).
63. Region completion: 1 star needed, 1 candidate (row 6, column 9).
64. Mark 3 cells adjacent to stars as X (row 5, column 8).
65. Region completion: 2 stars needed, 2 candidates (row 4, column 8).
66. Region completion: 1 star needed, 1 candidate (row 4, column 10).
67. Row 4 complete: Mark 1 remaining cell as X (row 4, column 6).
68. Region completion: 1 star needed, 1 candidate (row 5, column 6).
69. Column completion: 1 star needed, 1 candidate (row 10, column 8).
70. Mark 2 cells adjacent to stars as X (row 9, column 9).
71. Row 10 complete: Mark 4 remaining cells as X (row 10, column 2).
72. Region completion: 1 star needed, 1 candidate (row 9, column 2).
73. Mark 3 cells adjacent to stars as X (row 8, column 1).
74. Column 2 complete: Mark 1 remaining cell as X (row 5, column 2).
75. Row completion: 1 star needed, 1 candidate (row 5, column 3).
76. Mark 1 cell adjacent to stars as X (row 6, column 4).
77. Region completion: 1 star needed, 1 candidate (row 9, column 4).
78. Mark 1 cell adjacent to stars as X (row 8, column 5).
79. Region completion: 1 star needed, 1 candidate (row 7, column 5).
80. Row completion: 1 star needed, 1 candidate (row 6, column 1).
81. Mark 1 cell adjacent to stars as X (row 7, column 1).
82. Region completion: 1 star needed, 1 candidate (row 7, column 3).
83. Row 9 complete: Mark 1 remaining cell as X (row 9, column 10).
84. Column 9 complete: Mark 1 remaining cell as X (row 8, column 9).
85. Region completion: 1 star needed, 1 candidate (row 8, column 10).
86. Solved! Every row, column, and region has its two stars, none touching.