Grafite Sudoku
Printable Medium Sudoku #4
30 given numbers, medium level. At some point you need techniques beyond singles: write pencil marks.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 3 | 8 | 4 | ||||||
| 2 | 6 | 4 | 5 | ||||||
| 3 | 4 | 2 | |||||||
| 4 | 1 | 2 | 8 | 5 | 7 | ||||
| 5 | 4 | 1 | 7 | 3 | |||||
| 6 | 7 | 2 | 3 | 9 | 1 | ||||
| 7 | 7 | 3 | |||||||
| 8 | 8 | 9 | 7 | ||||||
| 9 | 7 | 8 | 9 |
Print on A4 or Letter paper without resizing. The solution is on page 2.
Show the solution
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 9 | 1 | 3 | 8 | 6 | 5 | 4 | 7 | 2 |
| 2 | 2 | 7 | 6 | 9 | 4 | 1 | 8 | 5 | 3 |
| 3 | 5 | 4 | 8 | 7 | 2 | 3 | 1 | 9 | 6 |
| 4 | 1 | 3 | 9 | 2 | 8 | 6 | 5 | 4 | 7 |
| 5 | 8 | 6 | 4 | 1 | 5 | 7 | 3 | 2 | 9 |
| 6 | 7 | 5 | 2 | 4 | 3 | 9 | 6 | 8 | 1 |
| 7 | 6 | 9 | 1 | 5 | 7 | 4 | 2 | 3 | 8 |
| 8 | 3 | 8 | 5 | 6 | 9 | 2 | 7 | 1 | 4 |
| 9 | 4 | 2 | 7 | 3 | 1 | 8 | 9 | 6 | 5 |
Where to start
Look at row 4, column 3: only one number fits there.
The rules
Every row, every column and every 3×3 box must contain the numbers 1 to 9, each exactly once.
Tips for solving it
- When the singles run out, write pencil marks in every empty cell of a box.
- Look for two cells with the same two candidates in a row: those numbers cannot go anywhere else in that row.
- If, inside a box, a number can only sit in one row, remove it from the rest of that row.
- Recheck your pencil marks after every number you write: that is where new steps hide.