## Problem with (very) hard puzzle

Advanced methods and approaches for solving Sudoku puzzles

### Problem with (very) hard puzzle

Hi there
I got stuck with this puzzle:
Code: Select all
`|-----|-----|-----||3 8 0|0 0 0|9 2 0||0 0 6|4 3 9|7 8 5||0 0 9|0 2 0|3 0 0||-----|-----|-----||0 6 0|0 9 0|0 0 0||8 0 0|3 0 2|0 0 9||9 0 0|0 4 0|0 7 0||-----|-----|-----||0 0 1|9 7 0|5 0 8||4 9 5|2 8 6|1 3 7||0 0 8|0 0 0|0 9 2||-----|-----|-----|`

Robert Craven

Posts: 6
Joined: 11 June 2005

Step one, look for a pair in column 3

Step two, look at the number 4... where can it go on row 5?

Step three, fill in a number on row 5. (and some in box 9 after that)
Animator

Posts: 469
Joined: 08 April 2005

Thanks for the fast reply. But I still cannot figure out wich numer to put in row 5

> Step one, look for a pair in column 3

There is a pair of <4,7> in 1 and 5, and a pair of <2,3> in 4 and 6.

> Step two, look at the number 4... where can it go on row 5?
2, 3, 7, 8

> Step three, fill in a number on row 5.

How?
Robert Craven

Posts: 6
Joined: 11 June 2005

Take a look at box 4. Where can the number 4 go?

Once you figured that out you know where it can go on row 5 and then there will be one cell with only one candidate.
Animator

Posts: 469
Joined: 08 April 2005

I go it. Thanks a lot.
It was not that hard. I was just blind. Probably I did too many Sudokus lately.
Robert Craven

Posts: 6
Joined: 11 June 2005