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March 17 VH

 
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Earl



Joined: 30 May 2007
Posts: 677
Location: Victoria, KS

PostPosted: Tue Mar 17, 2009 3:55 am    Post subject: March 17 VH Reply with quote

St. Patrick's Day brings an impish VH. This leprechaun found the pot gold at the end of the rainbow to be an xyz wing (259). There are alternate paths to the prize, such as a swordfish.

Early Earl
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Marty R.



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

PostPosted: Tue Mar 17, 2009 4:19 am    Post subject: Reply with quote

Same XYZ here, but I first played a UR, not because it was needed, but because it was there.

Tardy Marty
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sdq_pete



Joined: 30 Apr 2007
Posts: 119
Location: Rotterdam, NL

PostPosted: Tue Mar 17, 2009 1:23 pm    Post subject: Reply with quote

It was a XY for me. I didn't note it but I think it was 359 with pivot at R4C4.
Peter
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Tue Mar 17, 2009 5:49 pm    Post subject: Reply with quote

Quote:
There are alternate paths to the prize, such as a swordfish.

there two swordfish in the puzzle.
only one will solve it in one step

Code:
.---------------------.---------------------.---------------------.
| 7      56     8     | 9      56     4     | 13     13     2     |
| 3      569    59    | 15     156    2     | 8      7      4     |
| 2      4      1     | 8      3      7     | 5      6      9     |
:---------------------+---------------------+---------------------:
|W59     28     47    | 35     259    1     | 369    34589  3678  |
| 6     W59     3     | 4      7      8     | 2     W59     1     |
| 1      28     47    | 6      25    E39    |E39     458    78    |
:---------------------+---------------------+---------------------:
| 4      1      69    | 2      8      5     | 7      39     36    |
|W59     7      2569  | 13     4     3-9    | 169    1289   68    |
| 8      3      29    | 7      19     6     | 4      129    5     |
'---------------------'---------------------'---------------------'

one of the swordfish has a corresponding extended w-wing on {5,9}
the w-wing is marked with a W
the extension with a E
eliminates the 9 in r8c6
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crunched



Joined: 05 Feb 2008
Posts: 168

PostPosted: Wed Mar 18, 2009 12:59 am    Post subject: Reply with quote

The 25-59-259 xyz (see boxes 4 & 5) does it all. It takes out the 5 in r4c4, leaving a 3, and the puzzle unravels.

Code:

+---------------+-----------+-------------------+
| 7   56   8    | 9  56  4  | 13   13     2     |
| 359 3569 569  | 15 156 2  | 8    7      4     |
| 2   4    1    | 8  3   7  | 5    6      9     |
+---------------+-----------+-------------------+
| 59  28   47   | 35 259 1  | 369  34589  35678 |
| 6   59   3    | 4  7   8  | 2    59     1     |
| 1   28   47   | 6  25  39 | 39   34589  3578  |
+---------------+-----------+-------------------+
| 4   1    69   | 2  8   5  | 7    39     36    |
| 359 7    2569 | 13 4   39 | 1369 123589 3568  |
| 8   359  259  | 7  19  6  | 4    12359  35    |
+---------------+-----------+-------------------+

Play this puzzle online at the Daily Sudoku site
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nataraj



Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria

PostPosted: Wed Mar 18, 2009 7:56 am    Post subject: disappearing UR Reply with quote

Cheshire Cat Sudoku *): the vanishing rectangle.

I solved this one in a curious **) way.

About halfway into the puzzle (and with only some PMs filled in) I noticed a UR type 1 (39) in r68c67, which meant that r8c7 could not be 3 or 9.
I wrote down this information "for later".

When I was done with basics, the cell r8c7 had lost the candidate 3: the UR had disappeared.

But the elimination is still valid! So, taking out 9 from r8c7, I had 9 confined to col 7 in box 6 and thus r5c8=5. Singles/basics from there.

I usually don't use UR eliminations until lesser means like basics or obvious wings have worked their voodoo, but it makes sense to write down any eliminations, because the UR just might disappear ...

----
*) "How do you know I'm mad?" said nataraj.
"You must be," said the Sudoku, "otherwise you wouldn't have come here."

**) “Curiouser and curiouser!” Cried nataraj (he was so much surprised, that for the moment he quite forgot how to speak good English).
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nataraj



Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria

PostPosted: Wed Mar 18, 2009 5:46 pm    Post subject: Reply with quote

Embarassed Embarassed Embarassed

the UR I mentioned is NOT VALID !


A valid UR should not extend to four boxes

I must have been mad (the tea I had for breakfast ???)

(I still like the story: sometimes URs - REAL URs - do disappear)

Embarassed Embarassed Embarassed
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DennyOR



Joined: 12 Sep 2007
Posts: 33
Location: Portland, Oregon

PostPosted: Wed Mar 18, 2009 7:42 pm    Post subject: Reply with quote

And the 91-13-35-59 chain takes out the same 9 as the xy-wing.
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