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Clement
Joined: 24 Apr 2006 Posts: 779 Location: Dar es Salaam Tanzania

Posted: Fri Nov 16, 2012 11:02 pm Post subject: Nov 17 VH 


Code: 
++++
 1 6 23  23 4 9  8 7 5 
 7 45 245  6 1 8  9 24 3 
 *248 9 2348  23 5 7  246 1 *26 
++++
 *24 1 6  5 9 3  7 8 *24 
 9 3 28  7 68 4  26 5 1 
 458 7 458  1 68 2  3 9 46 
++++
 3 8 9  4 2 5  1 6 7 
 6 45 7  8 3 1  245 24 9 
 45 2 1  9 7 6  45 3 8 
++++
 XWing on 2 in col 19; r3c347<>2 opens an
XYWing 242848 pivoted in r5c3; r3c1<>4, r6c3<>4 solves it. 

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George Woods
Joined: 28 Mar 2006 Posts: 259 Location: Dorset UK

Posted: Sat Nov 17, 2012 11:13 am Post subject: another almost an xy! 


I didn't spot the x wing in 2s but used the xwing in 4s (cols 2 and 8 ) so r2c3 is not 4 and this set up an amost Xy wing pivoted in r5c3. so if r6c1 is not 4 it becomes 5 via the xy wing 258. else it is 4 so it cannot be 8 so r3c1 is 8 and this solves it! This logic can be tested by setting r6c1 to 8 and in two moves we can see that it is wrong since there is then no 5 in box 4
corrected after reading thecomment below thank yougeorge
Last edited by George Woods on Sat Nov 17, 2012 5:15 pm; edited 2 times in total 

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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills

Posted: Sat Nov 17, 2012 2:42 pm Post subject: Re: another almost an xy! 


George Woods wrote:  I didn't spot the x wing in 2s but used the xwing in 4s (cols 2 and 8 so r2c3 is not 4 and this set up an amost Xy wing pivoted in r5c3. so if r1c6 is not 4 it becomes 5 via the xy wing 258. else it is 4 so it cannot be 8 so r3c1 is 8 and this solves it! This logic can be tested by setting r1c6 to 8 and in two moves we can see that it is wrong since there is then no 5 in box 4 
George,
Nice find. I never expected anyone to use an "almost" pattern on this site, but they are easy to spot and very useful.
Your last comment about setting r6c1=8 (you had a typo: r1c6) is sufficient to complete the puzzle; the xwing(4) is not required.
Ted 

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Clement
Joined: 24 Apr 2006 Posts: 779 Location: Dar es Salaam Tanzania

Posted: Sun Nov 18, 2012 1:30 pm Post subject: Nov 17 VH 


George Woods
You have a different Grid from mine after basics? 

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George Woods
Joined: 28 Mar 2006 Posts: 259 Location: Dorset UK

Posted: Sun Nov 18, 2012 2:14 pm Post subject: different grid 


yes  after the x wing in 4s r2c3 is 25 hence the almost an xy wing and of course I didn't have the removal of 2s from your x wing in 2! 

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rebkell
Joined: 18 Nov 2012 Posts: 5

Posted: Sun Nov 18, 2012 5:53 pm Post subject: Re: Nov 17 VH 


Clement wrote:  Code: 
++++
 1 6 23  23 4 9  8 7 5 
 7 45 245  6 1 8  9 24 3 
 *248 9 2348  23 5 7  246 1 *26 
++++
 *24 1 6  5 9 3  7 8 *24 
 9 3 28  7 68 4  26 5 1 
 458 7 458  1 68 2  3 9 46 
++++
 3 8 9  4 2 5  1 6 7 
 6 45 7  8 3 1  245 24 9 
 45 2 1  9 7 6  45 3 8 
++++
 XWing on 2 in col 19; r3c347<>2 opens an
XYWing 242848 pivoted in r5c3; r3c1<>4, r6c3<>4 solves it. 
I'm still having problems solving this after all the xwing, xy wing I come up with this and I'm just a dunce, but I can't figure out how to solve it from here.
Code: 
++++
 1 6 3  2 4 9  8 7 5 
 7 45 245  6 1 8  9 24 3 
 28 9 48  3 5 7  46 1 246 
++++
 24 1 6  5 9 3  7 8 24 
 9 3 28  7 68 4  26 5 1 
 458 7 58  1 68 2  3 9 46 
++++
 3 8 9  4 2 5  1 6 7 
 6 45 7  8 3 1  245 24 9 
 45 2 1  9 7 6  45 3 8 
++++



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kuskey
Joined: 10 Dec 2008 Posts: 140 Location: Pembroke, NH

Posted: Sun Nov 18, 2012 7:03 pm Post subject: Nov 17 VH 


rebkell:
I see a 458 xy wing with pivot at r3c3 which makes r2c3<>5. This reveals a naked pair <24> in r2, setting r2c2<>4. Barring previous mistakes you should be off and running. 

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rebkell
Joined: 18 Nov 2012 Posts: 5

Posted: Sun Nov 18, 2012 8:21 pm Post subject: Re: Nov 17 VH 


kuskey wrote:  rebkell:
I see a 458 xy wing with pivot at r3c3 which makes r2c3<>5. This reveals a naked pair <24> in r2, setting r2c2<>4. Barring previous mistakes you should be off and running. 
Thanks, that did it, I should have seen that. I wasn't expecting another xywing I guess. 

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Clement
Joined: 24 Apr 2006 Posts: 779 Location: Dar es Salaam Tanzania

Posted: Mon Nov 19, 2012 1:29 pm Post subject: Nov 17 VH 


rebkell wrote
''I'm still having problems solving this after all the xwing, xy wing I come up with this and I'm just a dunce, but I can't figure out how to solve it from here''.
You are right, an xwing on 4 in row 46; r9c1<>4 was needed to comlete it. Sorry for the inconvinience 

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