## Having to guess?

Advanced methods and approaches for solving Sudoku puzzles

### Having to guess?

I have tried a very hard puzzle, got stuck, so went to various Sudoku solver sites which either can't solve it or can only solve it by guessing.

My initial puzzle:

**9 8** 16*
*** *** ***
2** **9 **8

*4* **7 *83
6** 2*4 **7
87* 3** *9*

5** 7** **4
*** *** ***
*28 **1 3**

This is as far as I get:

**9 8** 16*
*8* *** ***
2** **9 7*8

14* **7 *83
693 284 517
87* 31* 49*

5** 7** *24
*** *** **1
*28 **1 3**

Is there a way of solving it without guessing? I thought guessing was not part of these puzzles.

Any help much appreciated.

Thanks

David
david200110

Posts: 2
Joined: 18 June 2005

Use a 235 triple in row 1 and a 136 triple in block 7 to eliminate some 3's in column 1, deducing r2c1 = 3.
Scott H

Posts: 73
Joined: 28 July 2005

Very many thanks. Finally did it, but couldn't have without your tip. I'm not 100% confident with triplets and can't find a site with good explanation with examples.

david
david200110

Posts: 2
Joined: 18 June 2005

You can find a good explanation of triples (both naked and hidden, with an example of each) at angusj's site.
scrose

Posts: 322
Joined: 31 May 2005