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		| David Bryant 
 
 
 Joined: 29 Jul 2005
 Posts: 559
 Location: Denver, Colorado
 
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				|  Posted: Thu Mar 09, 2006 3:58 pm    Post subject: "Nightmare" for Thursday, 9 March, 2006 |   |  
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				| This puzzle isn't nearly as hard as the "zen" sudoku I posted here yesterday, but it's still plenty tough. I found two different "5-star constellations" before I was able to solve it. 
  	  | Code: |  	  | .6..2.... ..84..7.1
 ..16....2
 7..1.....
 ..9.7.6..
 .....4..3
 9....53..
 3.5..24..
 ....4..8.
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 Enjoy!  dcb
 
 PS In reworking this puzzle I noticed that the first "5-star constellation" I found was not really necessary -- there was a triplet {7, 8, 9} that would have served the same purpose, if I had only noticed it.
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		| keith 
 
 
 Joined: 19 Sep 2005
 Posts: 3355
 Location: near Detroit, Michigan, USA
 
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				|  Posted: Thu Mar 09, 2006 10:27 pm    Post subject: Color me again! |   |  
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				| David, 
 I found that early on there is a coloring on <7> which excludes that value from R9C3.  This is a big help.  Then, the puzzle can be solved via an X-wing on <3> (which also appears early), and the last step is an XY-wing on <9>.  (After that, all moves are forced.)
 
 Keith
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		| someone_somewhere 
 
 
 Joined: 07 Aug 2005
 Posts: 275
 Location: Munich
 
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				|  Posted: Sun Mar 12, 2006 2:51 pm    Post subject: |   |  
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				| Hi, Just tried this one, in order to check that I am still alive ...
 
 I foud for digit 3 a X-Wing on Column in: r2c2 r2c6 r5c2 r5c6
 so I could eliminate it from: r3c2, r3c6, r4c2, r4c6, r9c6
 and so 3 is in r9c4  as Unique Horizontal.
 
 Now I excluded 6 from r4c3,  because it would otherwise force a 6 in r9c1 and r9c6.
 
 Followed by 9 not in r3c5 because of an XY-wing (that I leave to you to find) and by 9 not in r4c6 because of an other similar XY-wing.
 
 Finally, I excluded 1 from r6c2, because it would give a contradiction on row with r9c1 and r9c7 for digit 1.
 
 P.S. galaxies behind the "zen" one !!!
 
 see u,
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