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Another Fiendish Puzzle

 
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garytorborg



Joined: 19 Jan 2011
Posts: 28

PostPosted: Mon Jan 31, 2011 9:50 pm    Post subject: Another Fiendish Puzzle Reply with quote

Thanks to all who helped me last time. I have since successfully solved several "fiendish" puzzles from the program I use, but have once again run into a brick wall.

After the basics, three x-wings (!), and an xy-wing, I have arrived at this position and am now stuck.
Code:

|-----|-----|-----|-----|-----|-----|-----|-----|-----|
| 89  |  5  |  4  | 128 | 189 |  7  |  3  |  6  | 12  |
|  1  | 689 |  3  |  5  | 689 | 289 |  4  | 29  |  7  |
|  7  |  2  | 69  |  3  | 169 |  4  |  5  |  8  | 19  |
|-----|-----|-----|-----|-----|-----|-----|-----|-----|
| 246 | 69  |  8  | 46  |  7  |  3  |  1  |  5  | 29  |
| 234 |  7  |  1  |  9  | 48  |  5  |  6  | 24  | 38  |
| 346 | 369 |  5  |1468 |  2  | 18  |  7  | 49  | 38  |
|-----|-----|-----|-----|-----|-----|-----|-----|-----|
| 89  |  1  | 29  |  7  |  5  |  6  | 28  |  3  |  4  |
|  5  | 38  |  7  | 248 | 348 | 28  |  9  |  1  |  6  |
| 36  |  4  | 26  | 18  |1389 | 189 | 28  |  7  |  5  |
|-----|-----|-----|-----|-----|-----|-----|-----|-----|


Include things like doubles, triples, and quads in the "basics". Anybody have an idea? Thanks in advance.
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

PostPosted: Mon Jan 31, 2011 10:23 pm    Post subject: Reply with quote

There's a W-Wing on the 69 cells in boxes 14, linked by the 9s in c9. That should make a big dent, maybe solve it.
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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK

PostPosted: Mon Jan 31, 2011 10:24 pm    Post subject: Reply with quote

You need a new type of wing - a w-wing!
Look at the two (69) bivalues in b1 and b4 - notice the aligned strong link on (9) in c9...
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garytorborg



Joined: 19 Jan 2011
Posts: 28

PostPosted: Mon Jan 31, 2011 10:31 pm    Post subject: Reply with quote

As far as I can see, the W-wing you describe only results in a single elimination: the 9 in r2c2, leaving 68. Any other further clues?
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Mon Jan 31, 2011 10:35 pm    Post subject: Reply with quote

If you are familiar with XY-Chains, then here is a 4-cell XY-Chain that cracks the puzzle.

Code:
 (4=6)r4c4 - (6=9)r4c2 - (9=2)r4c9 - (2=4)r5c8  =>  r5c5<>4
 +--------------------------------------------------------------+
 |  89    5     4     |  128   189   7     |  3     6     12    |
 |  1     689   3     |  5     689   289   |  4     29    7     |
 |  7     2     69    |  3     169   4     |  5     8     19    |
 |--------------------+--------------------+--------------------|
 |  246  b69    8     | a46    7     3     |  1     5    c29    |
 |  234   7     1     |  9     8-4   5     |  6    d24    38    |
 |  346   369   5     |  1468  2     18    |  7     49    38    |
 |--------------------+--------------------+--------------------|
 |  89    1     29    |  7     5     6     |  28    3     4     |
 |  5     38    7     |  248   348   28    |  9     1     6     |
 |  36    4     26    |  18    1389  189   |  28    7     5     |
 +--------------------------------------------------------------+
 # 55 eliminations remain
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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK

PostPosted: Mon Jan 31, 2011 10:48 pm    Post subject: Reply with quote

garytorborg wrote:
As far as I can see, the W-wing you describe only results in a single elimination: the 9 in r2c2, leaving 68. Any other further clues?

You have made the wrong elimination - it should be a r2c2<>6!
If r3c3 is not a 6 it must be a 9, so r3c9 is not a 9...
So r4c9 must be a 9 and hence r4c2 must be a 6.
Whatever one end of this chain must be a 6 and so r2c2<>6

Also you can eliminate the 9 from r2c2 because of locked 9s pointing in b4...

I think that cracks it.
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