force chain?

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force chain?

Postby flybriguy » Sun Nov 16, 2008 11:58 pm

I have the following puzzle which I am stuck on. I think I've managed one turbot fish elimination and one x-wing elimination thus far but I can't find anything else. Will I have to resort to a force chain method?

Code: Select all
5   7   69   |   1   24   8   |   49   3   246
46   2   8   |   9   3   7   |   1   5   46
1   49   3   |   24   5   6   |   7   8   249
---------------+-------------------+------------------
7   6   5   |   3   1   2   |   49   49   8
9   3   4   |   8   7   5   |   6   2   1   
2   8   1   |   6   9   4   |   3   7   5
---------------+-------------------+------------------
3   45   69   |   57   8   1   |   2   469   47
46   59   2   |   57   46   3   |   8   1   79
8   1   7   |   24   246   9   |   5   46   3



Source of puzzle is from mmgames "Expert Sudoku" for iPhone app, "skilled" level

Any suggestions where to go from here would be great. thanks.
flybriguy
 
Posts: 9
Joined: 15 November 2008

Postby flybriguy » Mon Nov 17, 2008 12:01 am

aaarrgh, apologies for this wonky grid. I can't seem to get this right even when using courier and using the code tags. I will repost if I can get it right.
flybriguy
 
Posts: 9
Joined: 15 November 2008

Postby eleven » Mon Nov 17, 2008 2:01 am

Code: Select all
+----------------+----------------+----------------+
| 5    7    69   | 1    24   8    | 49   3    246  |
| 46   2    8    | 9    3    7    | 1    5    46   |
| 1    49   3    | 24   5    6    | 7    8    249  |
+----------------+----------------+----------------+
| 7    6    5    | 3    1    2    | 49   49   8    |
| 9    3    4    | 8    7    5    | 6    2    1    |
| 2    8    1    | 6    9    4    | 3    7    5    |
+----------------+----------------+----------------+
| 3    45   69   | 57   8    1    | 2    469  47   |
| 46   59   2    | 57   46   3    | 8    1    79   |
| 8    1    7    | 24   246  9    | 5    46   3    |
+----------------+----------------+----------------+
In the first 2 rows you can find 2 xy-wings, each solving it.
Or: In row 7 there is a hidden pair/naked triple, which leads to a skyscraper in 4 in rows 27.
eleven
 
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Joined: 10 February 2008

Postby flybriguy » Mon Nov 17, 2008 3:09 am

thanks eleven . . . .

*ahhh I am blind to have not seen the hidden double

**xy-wing I've neglected to learn :P

brian
flybriguy
 
Posts: 9
Joined: 15 November 2008

Postby flybriguy » Mon Nov 17, 2008 4:14 am

ok just so I'm on good track here ... Does the xy-wing start with (r1,c3)? And thereby yz (r1,c7) and xz (r2,c1)? Then elimination on r2,c9?
flybriguy
 
Posts: 9
Joined: 15 November 2008

Postby Steve R » Mon Nov 17, 2008 5:41 am

Yes, one does.

The other is pivoted on r1c7 with pincers r1c3 and r2c9.

Steve
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Joined: 03 April 2006


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