## V Hard from Sudoku programme

Advanced methods and approaches for solving Sudoku puzzles

### V Hard from Sudoku programme

I cannot see any xwings or other clues to progress this puzzle. Any suggestions appreciated

*** *72 31*
*** 96* **5
**8 *43 *9*

1** *** *2*
7** *** **9
*5* *** **3

*** 316 9**
3** 784 ***
864 259 731
Arnie

Posts: 49
Joined: 19 May 2005

Look at box 1 you'll see only 1 number can go into r1c2
su_doku

Posts: 30
Joined: 19 March 2005

....r1c2 can have 4 or 9...
Arnie

Posts: 49
Joined: 19 May 2005

yes Arnie ignore previous post - mixed my pencil marks
su_doku

Posts: 30
Joined: 19 March 2005

Arnie check box 7 - the pairs in r8c2, r8c3 and r7c2, r7c3 should allow you to fill in r7c1
su_doku

Posts: 30
Joined: 19 March 2005

Take a close look at row 2...

And su_doku, are you sure about box 7? (as in, I can't see an immediate reason why it would be possible to fill in r7c1)
Animator

Posts: 469
Joined: 08 April 2005

Ignore what I said about row 2... it's incorrect aswell...
Animator

Posts: 469
Joined: 08 April 2005

as sure as I can be...

I see pair 1,9 in r8c2, r8c3 - that leaves 2,5 and 7 for the remaining 3 cells in box7.

But the two of column 1 is in box 1 (r2c1 or r3c1) - hence the pair of 2 and 7 in r7c2 and r7c3
su_doku

Posts: 30
Joined: 19 March 2005

It is correct, but you left an important hint out: first look at box 1, and pay extra attention to the numbers 1, 3 and 7.

(Spotting the pairs on row 8 and row 9 where easy, I wasn't seeing the one in box 1, which is why I was unsure if your hint was correct)
Animator

Posts: 469
Joined: 08 April 2005

Thanks - i now see the "triplet" of 1,3 and 7 in r2c2,3 and r3c2.
Arnie

Posts: 49
Joined: 19 May 2005

AFAIK:
R2C2 has candidates 1,2,3,4,7
R2C3 has candidates 1,2,3,7
R3C2 has candidates 1,2,7

There can only be a triplet if you have somehow eliminated the 2s and 4s? (or 3s and 4s)
Last edited by simes on Sun Dec 11, 2011 2:43 pm, edited 1 time in total.
simes

Posts: 324
Joined: 11 March 2005
Location: UK

Well OK, but a subset of 5 numbers? Did you spot this manually or have a little electronic help?
Last edited by simes on Sun Dec 11, 2011 2:44 pm, edited 1 time in total.
simes

Posts: 324
Joined: 11 March 2005
Location: UK

Take a different look at it... where can the numbers 1, 3 and 7 go? there are only three cells that can have one of those...
Animator

Posts: 469
Joined: 08 April 2005

Doh!

I was approaching from the other side. I stand corrected!
simes

Posts: 324
Joined: 11 March 2005
Location: UK