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Earl
Joined: 30 May 2007 Posts: 677 Location: Victoria, KS
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Posted: Thu Jun 07, 2007 4:25 pm Post subject: June 7 |
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Am I correct that June 7 is solved by two x-y wings:
r2c4,r9c4,r7c5 (eliminatng a 9 in r8c4) and r7c5,r7c9,r8c6 (eliminating 4's in r8c8 and r8c9)?
Earl |
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Lynnda
Joined: 07 Jun 2007 Posts: 3 Location: Sydney, Australia
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Posted: Thu Jun 07, 2007 11:23 pm Post subject: June 7 |
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Earl,
Thank you sooooo much. I am just learning to do these XY wings and your tip gave me the right squares to look at and find my first 2 in a "live" situation. Yep, it sure solved the puzzle for me once I had those |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Sat Jun 09, 2007 3:38 pm Post subject: Re: June 7 |
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Earl wrote: | Am I correct that June 7 is solved by two x-y wings:
r2c4,r9c4,r7c5 (eliminatng a 9 in r8c4) and r7c5,r7c9,r8c6 (eliminating 4's in r8c8 and r8c9)?
Earl |
I guess that's correct if the puzzle got solved. The question implies that there is a standard way to solve, but there are often many ways to solve a given puzzle. In my case there was a Type 4 rectangle which exposed an XY-Wing which solved the puzzle. Overall, this seemed a relatively easy VH. |
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Jeff
Joined: 06 May 2007 Posts: 46
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Posted: Sat Jun 09, 2007 7:10 pm Post subject: June 7 |
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I am interested in finding out where the Type 4 Rectangle is in the June 7 puzzle as per Marty R.'s comment. I would also like to find an explanation of the various rectangles. I tried to find a written explanation on all the rectangles that one may run into, but I could not find the site. Could you give me a link to the appropriate site.
Many thanks |
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Mesmin
Joined: 01 May 2007 Posts: 12 Location: Ontario
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Posted: Sat Jun 09, 2007 7:38 pm Post subject: |
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Brain Bashers has a good explanation of most of the 'standard' advanced techniques:
http://brainbashers.com/sudokuhelp.asp
The very and super hard puzzles often require (or at least can be) solved with unique rectangles if you want to practice. |
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keith
Joined: 19 Sep 2005 Posts: 3355 Location: near Detroit, Michigan, USA
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Posted: Sat Jun 09, 2007 7:52 pm Post subject: Be Unique! |
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Basic methods get you to here:
Code: | +----------------+----------------+-----------------+
| 4 1 2 | 7 8 69 | 59 369 35 |
| 7 8 5 | 69 3 1 | 249 469 246 |
| 3 9 6 | 4 5 2 | 1 8 7 |
+----------------+----------------+-----------------+
| 5 6 1 | 3 4 7 | 8 2 9 |
| 8 4 3 | 259# 29 59# | 6 7 1 |
| 2 7 9 | 1 6 8 | 45 34 35 |
+----------------+----------------+-----------------+
| 6 5 47@ | 8 29 3 | 2479@ 1 24 |
| 1 2 8 | 59# 7 459# | 3 469 46 |
| 9 3 47@ | 26 1 46 | 247@ 5 8 |
+----------------+----------------+-----------------+ |
The Type 4 UR in R79C37 is marked #. You can exclude <4> from R79C7.
Seldom identified, but more common than you might think, is the Type 6 UR marked # in R58C46. (There is one in today's DB puzzle, see the "Other Puzzles" Forum.)
The UR is also an X-wing on <5>. R5C6 and R8C4 must be <5>. If either is <9>, a deadly solution is forced. Similarly, <5> in either of R5C4 or R8C6 forces a deadly solution.
My guide to unique rectangles is here:
http://www.sudoku.com/forums/viewtopic.php?p=29105#29105
Best wishes,
Keith |
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