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Sudoku #1 — the solutions

The three Sudoku boards from October 1, 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

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

The solution

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

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

The solution

8 3 9 | 5 2 1 | 7 4 6
1 5 4 | 8 7 6 | 2 9 3
6 7 2 | 3 9 4 | 5 8 1
------+-------+------
4 6 7 | 1 5 3 | 9 2 8
5 8 1 | 9 4 2 | 3 6 7
2 9 3 | 7 6 8 | 1 5 4
------+-------+------
3 2 5 | 6 8 7 | 4 1 9
7 4 6 | 2 1 9 | 8 3 5
9 1 8 | 4 3 5 | 6 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. 53 steps; yours need not match, and any order that never guesses ends on the same grid.

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

Hard — 28 digits given

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

The board

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

The solution

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

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

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

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.