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Sudoku #9 — the solutions

The three Sudoku boards from October 9, 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

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

The solution

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

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

Medium — 32 digits given

Beyond singles, this board asks for a pointing line (2 times) and a naked pair (2 times).

The board

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

The solution

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

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

Hard — 27 digits given

Beyond singles, this board asks for a pointing line, a hidden pair and an XY-wing.

The board

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

The solution

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

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. 57 steps; yours need not match, and any order that never guesses ends on the same grid.

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