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Sudoku #28 — the solutions

The three Sudoku boards from October 28, 2026 — Easy, Medium and Hard — each with its solved grid and a path through it, step by step, that never needs a guess.

Easy — 36 digits given

Every cell falls to scanning: a digit with only one place left in a row, a column or a box.

The board

· · 5 | · · · | · 3 ·
· · · | 5 2 4 | 1 8 ·
· · · | · 9 · | 2 5 ·
------+-------+------
7 · · | · 4 5 | · 1 3
· 2 8 | 9 · 3 | 7 4 ·
3 4 · | 6 7 · | · · 5
------+-------+------
· 1 2 | · 3 · | · · ·
· 5 7 | 8 6 2 | · · ·
· 3 · | · · · | 4 · ·

The solution

2 9 5 | 7 8 1 | 6 3 4
6 7 3 | 5 2 4 | 1 8 9
1 8 4 | 3 9 6 | 2 5 7
------+-------+------
7 6 9 | 2 4 5 | 8 1 3
5 2 8 | 9 1 3 | 7 4 6
3 4 1 | 6 7 8 | 9 2 5
------+-------+------
9 1 2 | 4 3 7 | 5 6 8
4 5 7 | 8 6 2 | 3 9 1
8 3 6 | 1 5 9 | 4 7 2

A path through it

The order a solver takes — always the cheapest move left, so a pattern is only reached for when the singles run dry. 45 steps; yours need not match, and any order that never guesses ends on the same grid.

  1. Row 1, column 1 is 2. 2 has only one place left in the top-left box.
  2. Row 3, column 4 is 3. 3 has only one place left in the top-center box.
  3. Row 2, column 3 is 3. 3 has only one place left in the top-left box.
  4. Row 5, column 1 is 5. 5 has only one place left in the middle-left box.
  5. Row 6, column 3 is 1. 1 has only one place left in the middle-left box.
  6. Row 3, column 1 is 1. 1 has only one place left in the top-left box.
  7. Row 3, column 3 is 4. 4 has only one place left in the top-left box.
  8. Row 1, column 9 is 4. 4 has only one place left in the top-right box.
  9. Row 5, column 5 is 1. 1 has only one place left in the center box.
  10. Row 4, column 4 is 2. 2 has only one place left in the center box.
  11. Row 6, column 6 is 8. 8 has only one place left in the center box.
  12. Row 1, column 5 is 8. 8 has only one place left in the top-center box.
  13. Row 3, column 2 is 8. 8 has only one place left in the top-left box.
  14. Row 6, column 8 is 2. 2 has only one place left in the middle-right box.
  15. Row 4, column 7 is 8. 8 has only one place left in the middle-right box.
  16. Row 5, column 9 is 6. 6 has only one place left in the middle-right box.
  17. Row 1, column 7 is 6. 6 has only one place left in the top-right box.
  18. Row 3, column 6 is 6. 6 has only one place left in the top-center box.
  19. Row 2, column 9 is 9. 9 has only one place left in the top-right box.
  20. Row 1, column 2 is 9. 9 has only one place left in the top-left box.
  21. Row 2, column 2 is 7. 7 has only one place left in the top-left box.
  22. Row 2, column 1 is 6. 6 has only one place left in the top-left box.
  23. Row 3, column 9 is 7. 7 has only one place left in the top-right box.
  24. Row 4, column 3 is 9. 9 has only one place left in the middle-left box.
  25. Row 4, column 2 is 6. 6 has only one place left in the middle-left box.
  26. Row 6, column 7 is 9. 9 has only one place left in the middle-right box.
  27. Row 9, column 3 is 6. 6 has only one place left in the bottom-left box.
  28. Row 7, column 4 is 4. 4 has only one place left in the bottom-center box.
  29. Row 8, column 1 is 4. 4 has only one place left in the bottom-left box.
  30. Row 9, column 5 is 5. 5 has only one place left in the bottom-center box.
  31. Row 9, column 9 is 2. 2 has only one place left in the bottom-right box.
  32. Row 8, column 9 is 1. 1 has only one place left in the bottom-right box.
  33. Row 8, column 7 is 3. 3 has only one place left in the bottom-right box.
  34. Row 7, column 7 is 5. 5 has only one place left in the bottom-right box.
  35. Row 7, column 8 is 6. 6 has only one place left in the bottom-right box.
  36. Row 9, column 8 is 7. 7 has only one place left in the bottom-right box.
  37. Row 7, column 6 is 7. 7 has only one place left in the bottom-center box.
  38. Row 1, column 4 is 7. 7 has only one place left in the top-center box.
  39. Row 1, column 6 is 1. 1 has only one place left in the top-center box.
  40. Row 9, column 4 is 1. 1 has only one place left in the bottom-center box.
  41. Row 9, column 6 is 9. 9 has only one place left in the bottom-center box.
  42. Row 7, column 1 is 9. 9 has only one place left in the bottom-left box.
  43. Row 9, column 1 is 8. 8 has only one place left in the bottom-left box.
  44. Row 7, column 9 is 8. 8 has only one place left in the bottom-right box.
  45. Row 8, column 8 is 9. 9 has only one place left in the bottom-right box.

Medium — 29 digits given

Beyond singles, this board asks for a pointing line.

The board

· · · | · 5 · | 4 · ·
3 · · | 9 · · | · 6 ·
· 1 · | · 6 · | 3 9 ·
------+-------+------
· · · | · · 2 | · 7 9
4 · · | 7 1 5 | · · 8
2 7 · | 6 · · | · · ·
------+-------+------
· 3 8 | · 7 · | · 1 ·
· 4 · | · · 9 | · · 3
· · 1 | · 3 · | · · ·

The solution

7 6 9 | 2 5 3 | 4 8 1
3 5 4 | 9 8 1 | 7 6 2
8 1 2 | 4 6 7 | 3 9 5
------+-------+------
1 8 6 | 3 4 2 | 5 7 9
4 9 3 | 7 1 5 | 6 2 8
2 7 5 | 6 9 8 | 1 3 4
------+-------+------
9 3 8 | 5 7 4 | 2 1 6
6 4 7 | 1 2 9 | 8 5 3
5 2 1 | 8 3 6 | 9 4 7

A path through it

The order a solver takes — always the cheapest move left, so a pattern is only reached for when the singles run dry. 53 steps; yours need not match, and any order that never guesses ends on the same grid.

  1. Row 4, column 1 is 1. 1 has only one place left in the middle-left box.
  2. Row 4, column 2 is 8. 8 has only one place left in the middle-left box.
  3. Row 6, column 5 is 9. 9 has only one place left in the center box.
  4. Row 6, column 6 is 8. 8 has only one place left in the center box.
  5. Row 4, column 4 is 3. 3 has only one place left in the center box.
  6. Row 1, column 6 is 3. 3 has only one place left in the top-center box.
  7. Row 4, column 5 is 4. 4 has only one place left in the center box.
  8. Row 8, column 4 is 1. 1 has only one place left in the bottom-center box.
  9. Row 2, column 6 is 1. 1 has only one place left in the top-center box.
  10. Row 3, column 6 is 7. 7 has only one place left in the top-center box.
  11. Row 3, column 4 is 4. 4 has only one place left in the top-center box.
  12. Row 2, column 3 is 4. 4 has only one place left in the top-left box.
  13. Row 1, column 9 is 1. 1 has only one place left in the top-right box.
  14. Row 6, column 7 is 1. 1 has only one place left in the middle-right box.
  15. Row 3, column 1 is 8. 8 has only one place left in row 3.
  16. In the middle-left box, 5 can only sit in column 3, so it leaves the rest of that column.
  17. Row 2, column 2 is 5. 5 has only one place left in the top-left box.
  18. Row 3, column 9 is 5. 5 has only one place left in the top-right box.
  19. Row 3, column 3 is 2. 2 has only one place left in row 3.
  20. Row 9, column 2 is 2. 2 has only one place left in the bottom-left box.
  21. Row 6, column 9 is 4. Nothing but 4 is left for this cell.
  22. Row 9, column 8 is 4. 4 has only one place left in the bottom-right box.
  23. Row 7, column 6 is 4. 4 has only one place left in the bottom-center box.
  24. Row 9, column 6 is 6. 6 has only one place left in the bottom-center box.
  25. Row 7, column 9 is 6. 6 has only one place left in column 9.
  26. Row 2, column 9 is 2. 2 has only one place left in column 9.
  27. Row 1, column 4 is 2. 2 has only one place left in the top-center box.
  28. Row 2, column 5 is 8. 8 has only one place left in the top-center box.
  29. Row 2, column 7 is 7. 7 has only one place left in the top-right box.
  30. Row 1, column 8 is 8. 8 has only one place left in the top-right box.
  31. Row 8, column 5 is 2. 2 has only one place left in the bottom-center box.
  32. Row 9, column 4 is 8. 8 has only one place left in the bottom-center box.
  33. Row 7, column 4 is 5. 5 has only one place left in the bottom-center box.
  34. Row 7, column 7 is 2. 2 has only one place left in the bottom-right box.
  35. Row 5, column 8 is 2. 2 has only one place left in the middle-right box.
  36. Row 6, column 8 is 3. 3 has only one place left in the middle-right box.
  37. Row 5, column 3 is 3. 3 has only one place left in the middle-left box.
  38. Row 5, column 2 is 9. 9 has only one place left in the middle-left box.
  39. Row 4, column 3 is 6. 6 has only one place left in the middle-left box.
  40. Row 6, column 3 is 5. 5 has only one place left in the middle-left box.
  41. Row 4, column 7 is 5. 5 has only one place left in the middle-right box.
  42. Row 5, column 7 is 6. 6 has only one place left in the middle-right box.
  43. Row 8, column 1 is 6. 6 has only one place left in the bottom-left box.
  44. Row 1, column 2 is 6. 6 has only one place left in the top-left box.
  45. Row 9, column 1 is 5. 5 has only one place left in the bottom-left box.
  46. Row 8, column 3 is 7. 7 has only one place left in the bottom-left box.
  47. Row 1, column 1 is 7. 7 has only one place left in the top-left box.
  48. Row 1, column 3 is 9. 9 has only one place left in the top-left box.
  49. Row 7, column 1 is 9. 9 has only one place left in the bottom-left box.
  50. Row 8, column 8 is 5. 5 has only one place left in the bottom-right box.
  51. Row 9, column 9 is 7. 7 has only one place left in the bottom-right box.
  52. Row 8, column 7 is 8. 8 has only one place left in the bottom-right box.
  53. Row 9, column 7 is 9. 9 has only one place left in the bottom-right box.

Hard — 28 digits given

Beyond singles, this board asks for a pointing line (4 times), a naked pair (2 times) and an XY-wing.

The board

· · · | 7 2 · | 1 · 4
· · 9 | · · 3 | · · ·
· · · | · · · | 2 · 8
------+-------+------
5 · 3 | · 7 · | 6 · ·
· · 8 | 6 · 2 | 3 · ·
· · 6 | · 1 · | 8 · 7
------+-------+------
3 · 1 | · · · | · · ·
· · · | 9 · · | 7 · ·
7 · 2 | · 5 8 | · · ·

The solution

6 8 5 | 7 2 9 | 1 3 4
2 4 9 | 1 8 3 | 5 7 6
1 3 7 | 5 4 6 | 2 9 8
------+-------+------
5 1 3 | 8 7 4 | 6 2 9
4 7 8 | 6 9 2 | 3 5 1
9 2 6 | 3 1 5 | 8 4 7
------+-------+------
3 9 1 | 2 6 7 | 4 8 5
8 5 4 | 9 3 1 | 7 6 2
7 6 2 | 4 5 8 | 9 1 3

A path through it

The order a solver takes — always the cheapest move left, so a pattern is only reached for when the singles run dry. 60 steps; yours need not match, and any order that never guesses ends on the same grid.

  1. Row 5, column 2 is 7. 7 has only one place left in the middle-left box.
  2. Row 3, column 3 is 7. 7 has only one place left in the top-left box.
  3. Row 2, column 8 is 7. 7 has only one place left in the top-right box.
  4. Row 6, column 4 is 3. 3 has only one place left in the center box.
  5. Row 6, column 6 is 5. 5 has only one place left in the center box.
  6. Row 4, column 4 is 8. 8 has only one place left in the center box.
  7. Row 2, column 5 is 8. 8 has only one place left in the top-center box.
  8. Row 7, column 4 is 2. 2 has only one place left in the bottom-center box.
  9. Row 8, column 5 is 3. 3 has only one place left in the bottom-center box.
  10. Row 7, column 6 is 7. 7 has only one place left in the bottom-center box.
  11. Row 8, column 3 is 4. 4 has only one place left in column 3.
  12. Row 1, column 3 is 5. 5 has only one place left in column 3.
  13. Row 9, column 9 is 3. 3 has only one place left in column 9.
  14. Row 2, column 7 is 5. Nothing but 5 is left for this cell.
  15. Row 3, column 4 is 5. 5 has only one place left in the top-center box.
  16. Row 2, column 9 is 6. Nothing but 6 is left for this cell.
  17. In the top-right box, 9 can only sit in column 8, so it leaves the rest of that column.
  18. In the middle-right box, 4 can only sit in column 8, so it leaves the rest of that column.
  19. In the middle-right box, 9 can only sit in column 9, so it leaves the rest of that column.
  20. Row 7, column 9 is 5. Nothing but 5 is left for this cell.
  21. Row 5, column 8 is 5. 5 has only one place left in the middle-right box.
  22. Row 8, column 2 is 5. 5 has only one place left in the bottom-left box.
  23. In the bottom-left box, 9 can only sit in column 2, so it leaves the rest of that column.
  24. Row 6, column 1 is 9. 9 has only one place left in row 6.
  25. Row 2, column 1 is 2. 2 has only one place left in column 1.
  26. Two cells in column 1 hold only 6 and 8, so no other cell there can.
  27. Two cells in the top-left box hold only 1 and 4, so no other cell there can.
  28. XY-wing: one of its two wings must be 6, so no cell that sees both can be.
  29. Row 7, column 8 is 8. Nothing but 8 is left for this cell.
  30. Row 8, column 1 is 8. 8 has only one place left in the bottom-left box.
  31. Row 1, column 2 is 8. 8 has only one place left in the top-left box.
  32. Row 3, column 2 is 3. 3 has only one place left in the top-left box.
  33. Row 1, column 1 is 6. 6 has only one place left in the top-left box.
  34. Row 1, column 8 is 3. 3 has only one place left in the top-right box.
  35. Row 3, column 8 is 9. 9 has only one place left in the top-right box.
  36. Row 1, column 6 is 9. 9 has only one place left in the top-center box.
  37. Row 5, column 5 is 9. 9 has only one place left in the center box.
  38. Row 4, column 6 is 4. 4 has only one place left in the center box.
  39. Row 6, column 8 is 4. 4 has only one place left in the middle-right box.
  40. Row 5, column 1 is 4. 4 has only one place left in the middle-left box.
  41. Row 2, column 2 is 4. 4 has only one place left in the top-left box.
  42. Row 3, column 1 is 1. 1 has only one place left in the top-left box.
  43. Row 2, column 4 is 1. 1 has only one place left in the top-center box.
  44. Row 3, column 5 is 4. 4 has only one place left in the top-center box.
  45. Row 3, column 6 is 6. 6 has only one place left in the top-center box.
  46. Row 4, column 2 is 1. 1 has only one place left in the middle-left box.
  47. Row 6, column 2 is 2. 2 has only one place left in the middle-left box.
  48. Row 5, column 9 is 1. 1 has only one place left in the middle-right box.
  49. Row 4, column 9 is 9. 9 has only one place left in the middle-right box.
  50. Row 4, column 8 is 2. 2 has only one place left in the middle-right box.
  51. Row 8, column 6 is 1. 1 has only one place left in the bottom-center box.
  52. Row 9, column 4 is 4. 4 has only one place left in the bottom-center box.
  53. Row 7, column 5 is 6. 6 has only one place left in the bottom-center box.
  54. Row 9, column 2 is 6. 6 has only one place left in the bottom-left box.
  55. Row 7, column 2 is 9. 9 has only one place left in the bottom-left box.
  56. Row 9, column 8 is 1. 1 has only one place left in the bottom-right box.
  57. Row 8, column 9 is 2. 2 has only one place left in the bottom-right box.
  58. Row 7, column 7 is 4. 4 has only one place left in the bottom-right box.
  59. Row 8, column 8 is 6. 6 has only one place left in the bottom-right box.
  60. Row 9, column 7 is 9. 9 has only one place left in the bottom-right box.

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About Sudoku

Sudoku on Noggin is three boards a day, on the second shelf: every entry is checked at once, a hint fills the next cell a solver would and says why, and the first board finished is the day’s score, outside the daily line-up. How to play Sudoku, or play today’s.