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Clement
Joined: 24 Apr 2006
Posts: 1111
Location: Dar es Salaam Tanzania
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 Posted: Mon Aug 30, 2010 10:56 pm Post subject: Aug 31 VH |
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Two steps(XY-Wings):-
1) XY-Wing 14 16 46 Pivoted in r9c1 removes 4 in r4c4 opens another
2) XY-Wing 67 47 46 with Pivot in r1c1 eliminating 6 in r7c6 solving the puzzle. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Tue Aug 31, 2010 4:18 am Post subject: |
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I would probably not have used this DP had Nataraj not posted his very similar DP here just today:
http://www.dailysudoku.co.uk/sudoku/forums/viewtopic.php?t=5035
Here's my grid after basics:
| Code: |
+-------------+-------------+---------+
| 478 1 3 | 4678 48 46 | 2 9 5 |
| 89 6 2 | 5 19 3 | 18 4 7 |
| 4789 5 47 | 478 19 2 | 6 3 18 |
+-------------+-------------+---------+
| 14 9 145 | 48 458 7 | 3 2 6 |
| 2 8 46 | 3 46 1 | 7 5 9 |
| 3 7 56 | 2 56 9 | 48 1 48 |
+-------------+-------------+---------+
| 67 34 9 | 1 27 46 | 5 8 23 |
| 5 34 17 | 9 27 8 | 14 6 23 |
| 16 2 8 | 46 3 5 | 9 7 14 |
+-------------+-------------+---------+
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Play this puzzle online at the Daily Sudoku site
There is a potential DP 45-46-56 in r456, c35. The DP can be broken up by the 8 in r4c5 or the 1 in r4c3. The 8 proves a 1 in r9c1 and this acts as a pincer with the 1 in r4c3, eliminating 1s in boxes 47, solving the puzzle. |
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kuskey
Joined: 10 Dec 2008
Posts: 141
Location: Pembroke, NH
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| Posted: Tue Aug 31, 2010 4:34 am Post subject: 31 Aug VH |
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| I agree with Clement but would add that the 467 xy-wing can be played two ways;with the pivot at r1c1 eliminating 6 in r7c6, or with the pivot at r7c1 eliminating 4 at r1c6 - somewhat unusual, I think. |
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Clement
Joined: 24 Apr 2006
Posts: 1111
Location: Dar es Salaam Tanzania
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| Posted: Tue Aug 31, 2010 7:02 pm Post subject: Aug 31 VH |
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Kuskey,
It is quite O.K. It occurs several times for the same configuration in an XY wing to have different pivots. I did not notice that one. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Tue Aug 31, 2010 8:00 pm Post subject: |
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this is Marty's brilliant find.
 |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Tue Aug 31, 2010 9:27 pm Post subject: |
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| Quote: | | this is Marty's brilliant find. |
Thanks very much, but most of the credit should probably go to Nataraj. |
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Luke451
Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California
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| Posted: Wed Sep 01, 2010 1:53 pm Post subject: |
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It has been interesting to watch the emergence of BUG-Lite use lately. With Marty's find, along with Nataraj's and Keith's last month, we'll have to retire the "rare" label soon  .
Since this BUG-Lite provides the strong link (1)r4c3=(8)r4c5, I would express it as an AIC.
| Code: | *-----------------------------------------------------------*
| 478 1 3 | 4678 48 46 | 2 9 5 |
| 89 6 2 | 5 19 3 | 18 4 7 |
| 4789 5 47 | 478 19 2 | 6 3 18 |
|-------------------+-------------------+-------------------|
| 14 9 145 | 48 458 7 | 3 2 6 |
| 2 8 46 | 3 46 1 | 7 5 9 |
| 3 7 56 | 2 56 9 | 48 1 48 |
|-------------------+-------------------+-------------------|
| 67 34 9 | 1 27 46 | 5 8 23 |
| 5 34 17 | 9 27 8 | 14 6 23 |
| 16 2 8 | 46 3 5 | 9 7 14 |
*-----------------------------------------------------------*
(1)r4c3=(8)r4c5-(8=4)r4c4-(4=6)r9c4-(6=1)r9c1 =>r4c1<>1 |
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sheryl
Joined: 24 Sep 2007
Posts: 64
Location: New York
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| Posted: Wed Sep 01, 2010 2:39 pm Post subject: where are the xy wings |
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clement,
can you please specify row and columns for the first 14, 16, 46 xy wing. i have all those numbers but they don't form an xy wing for me. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Wed Sep 01, 2010 3:57 pm Post subject: Re: where are the xy wings |
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| sheryl wrote: | clement,
can you please specify row and columns for the first 14, 16, 46 xy wing. i have all those numbers but they don't form an xy wing for me. |
I'm not Clement, but check the grid immediately above your post. The pivot (16) is in r9c1 and the others (14,46) are in r4c1 and r9c4. |
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sheryl
Joined: 24 Sep 2007
Posts: 64
Location: New York
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| Posted: Wed Sep 01, 2010 4:21 pm Post subject: thank you |
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it was right in front of me  |
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