Hard Star Battle answer — January 1, 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 5, 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 7, column 4).
4. Blocking rule: a star here would touch every other open cell in its region, leaving no room for the region's second star (row 7, column 6).
5. Three candidates with two adjacent: Isolated candidate must hold a star (row 8, column 7).
6. Mark 7 cells adjacent to stars as X (row 7, column 7).
7. Region completion: 1 star needed, 1 candidate (row 8, column 5).
8. Mark 4 cells adjacent to stars as X (row 7, column 5).
9. Row 8 complete: Mark 4 remaining cells as X (row 8, column 1).
10. Three candidates with two adjacent: Isolated candidate must hold a star (row 7, column 3).
11. Mark 4 cells adjacent to stars as X (row 6, column 2).
12. Region completion: 1 star needed, 1 candidate (row 6, column 5).
13. Mark 4 cells adjacent to stars as X (row 5, column 4).
14. Column 5 complete: Mark 4 remaining cells as X (row 1, column 5).
15. Three candidates with two adjacent: Isolated candidate must hold a star (row 5, column 3).
16. Mark 3 cells adjacent to stars as X (row 4, column 2).
17. Column 3 complete: Mark 4 remaining cells as X (row 1, column 3).
18. Three candidates in a column: Middle cell can't hold a star (row 2, column 4).
19. Column completion: 2 stars needed, 2 candidates (row 1, column 4).
20. Column completion: 1 star needed, 1 candidate (row 3, column 4).
21. Clump analysis (Row 9): each clump must supply its full share of stars (row 9, column 9).
22. Clump analysis (Column 6): candidate clumps can only just supply the remaining stars (row 1, column 7).
23. Two last candidates (column 7): Eliminate 2 cells adjacent to both (row 5, column 8).
24. Clump analysis (Column 8): candidate clumps can only just supply the remaining stars (row 3, column 9).
25. Row completion: 1 star needed, 1 candidate (row 1, column 8).
26. Mark 1 cell adjacent to stars as X (row 2, column 9).
27. Region completion: 1 star needed, 1 candidate (row 3, column 8).
28. Mark 1 cell adjacent to stars as X (row 4, column 8).
29. Row 3 complete: Mark 3 remaining cells as X (row 3, column 1).
30. Region completion: 1 star needed, 1 candidate (row 2, column 6).
31. Row completion: 2 stars needed, 2 candidates (row 4, column 1).
32. Mark 1 cell adjacent to stars as X (row 5, column 1).
33. Row completion: 1 star needed, 1 candidate (row 4, column 6).
34. Mark 1 cell adjacent to stars as X (row 5, column 7).
35. Region completion: 1 star needed, 1 candidate (row 5, column 9).
36. Mark 1 cell adjacent to stars as X (row 6, column 9).
37. Column completion: 2 stars needed, 2 candidates (row 2, column 2).
38. Mark 1 cell adjacent to stars as X (row 2, column 1).
39. Column completion: 1 star needed, 1 candidate (row 9, column 2).
40. Mark 1 cell adjacent to stars as X (row 9, column 1).
41. Column completion: 1 star needed, 1 candidate (row 6, column 7).
42. Region complete: Mark 1 remaining cell as X (row 7, column 9).
43. Row 6 complete: Mark 1 remaining cell as X (row 6, column 1).
44. Region completion: 1 star needed, 1 candidate (row 7, column 1).
45. Solved! Every row, column, and region has its two stars, none touching.