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March 20 VH

 
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Earl



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

PostPosted: Fri Mar 20, 2009 2:48 am    Post subject: March 20 VH Reply with quote

Many and multiple paths appeared, but the obvious (35) w-wing, eliminating the <5> in R1C9 did it solo. Coloring <3> or a finned x-wing <3> eliminate the <3> in R1C7, and are also single shots.

Early Earl
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crunched



Joined: 05 Feb 2008
Posts: 168

PostPosted: Fri Mar 20, 2009 6:20 am    Post subject: Reply with quote

Several xy wings were found (3 or 4). Dunno if all were needed, but the puzzle was solved with xy wings.
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Fri Mar 20, 2009 7:07 am    Post subject: Reply with quote

Code:

+-------------------+-------------+--------------------+
| 34   6      1345  | 9    7  2   | 358    458    345  |
| 9    245    2345  | 1    35 368 | 235678 245678 3457 |
| 8    25     7     | 36   4  36  | 23569  256    1    |
+-------------------+-------------+--------------------+
|#247  3      246   | 5    8  46  | 1     246-7   9    |
| 1    2479   2469  | 2367 23 346 | 2567   24567  8    |
| 5    247    8     | 267  9  1   | 267    3      47   |
+-------------------+-------------+--------------------+
| 6    5789   359   | 38   1  389 | 4     #578    2    |
|#2347 124789 12349 | 238  23 5   |#378  [1]78    6    |
| 23   1258   1235  | 4    6  7   | 358    9      35   |
+-------------------+-------------+--------------------+

Play this puzzle online at the Daily Sudoku site

this is the grid without any basics performed
notice that you can place a 1 in box 9 in r8c8
that now provides a coloring move on 7 marked #
this eliminates the 7 in r4c8
and should pave the way for basics to take you home.

nataraj mentioned finding an advanced technique early and employing it early, and this one proves costly for the puzzle.
poor puzzle, its life expectancy was about 5 mins after that.
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sdq_pete



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

PostPosted: Fri Mar 20, 2009 11:06 am    Post subject: Reply with quote

Well, this was my position after basics:
Code:

+--------------+-------------+---------------+
| 34  6    1   | 9    7  2   | 35   8    345 |
| 9   24   234 | 1    5  8   | 367  467  347 |
| 8   5    7   | 36   4  36  | 9    2    1   |
+--------------+-------------+---------------+
| 247 3    246 | 5    8  46  | 1    467  9   |
| 1   479  469 | 2367 23 346 | 2567 4567 8   |
| 5   47   8   | 26   9  1   | 26   3    47  |
+--------------+-------------+---------------+
| 6   578  35  | 38   1  9   | 4    57   2   |
| 347 4789 349 | 238  23 5   | 37   1    6   |
| 23  1    235 | 4    6  7   | 8    9    35  |
+--------------+-------------+---------------+

Play this puzzle online at the Daily Sudoku site
Then two XY's, 357 and 347, pivots R7C8 and R8C1

Peter
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HiMom



Joined: 02 Mar 2009
Posts: 3

PostPosted: Fri Mar 20, 2009 11:27 am    Post subject: One-step XYZ-wing did it for me Reply with quote

XYZ-wing 34-345-35 in the corners eliminated the 3 in r9c1
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LloydB



Joined: 09 Jul 2007
Posts: 21
Location: Skagit Co., WA USA

PostPosted: Fri Mar 20, 2009 12:04 pm    Post subject: Reply with quote

If you recognize the 235 triple in box 7 of Peter's diagram then only the 347 xy wing was needed.
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cgordon



Joined: 04 May 2007
Posts: 769
Location: ontario, canada

PostPosted: Fri Mar 20, 2009 2:44 pm    Post subject: Reply with quote

No one seems to have spotted the single step ER on 7 (C1,B9 removes 7 from R4C8) - though you need to be exceptionally skilled to spot that.
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Marty R.



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

PostPosted: Fri Mar 20, 2009 3:35 pm    Post subject: Re: One-step XYZ-wing did it for me Reply with quote

HiMom wrote:
XYZ-wing 34-345-35 in the corners eliminated the 3 in r9c1

Hi, HiMom,

Could you elaborate? I'm not seeing it.
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gindaani



Joined: 06 Mar 2009
Posts: 79

PostPosted: Fri Mar 20, 2009 4:08 pm    Post subject: Reply with quote

I had the same as sdq_pete after the basics, except no 5 in r7c2 which is impossible.

A skyscraper on 7s solved it in one step. It was pretty easy to spot too.
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Fri Mar 20, 2009 5:35 pm    Post subject: Reply with quote

cgordon wrote:
No one seems to have spotted the single step ER on 7 (C1,B9 removes 7 from R4C8) - though you need to be exceptionally skilled to spot that.


Craig,
yes. someone did post about it before you did.

Very Happy Very Happy Very Happy
Cool Cool Cool
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cgordon



Joined: 04 May 2007
Posts: 769
Location: ontario, canada

PostPosted: Fri Mar 20, 2009 8:31 pm    Post subject: Reply with quote

Quote:
Craig, yes. someone did post about it before you did.


I'm sorry but I scrolled back and saw xy this, colour this, fin this - but nothing alluding to my ER elegance.
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eddieg



Joined: 12 Jan 2006
Posts: 47
Location: San Diego, CA USA

PostPosted: Fri Mar 20, 2009 8:45 pm    Post subject: Loved today's puzzle Reply with quote

Best one in a long time.
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Fri Mar 20, 2009 10:00 pm    Post subject: Reply with quote

cgordon wrote:
Quote:
Craig, yes. someone did post about it before you did.


I'm sorry but I scrolled back and saw xy this, colour this, fin this - but nothing alluding to my ER elegance.

craig,
if you look at my first post in the this thread, I believe it makes mention of the 7's and does exactly what you did.
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cgordon



Joined: 04 May 2007
Posts: 769
Location: ontario, canada

PostPosted: Fri Mar 20, 2009 10:58 pm    Post subject: Reply with quote

Quote:
craig, if you look at my first post in the this thread, I believe it makes mention of the 7's and does exactly what you did.


Norm: Yes you may be right. But you never mentioned ERs. And this is my contention. Solutions should relate to recognisable techniques such as Wings , ERs or URs - otherwise the solutions become convoluted and esoteric solutions that transend the enjoyment of the masses.
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Sat Mar 21, 2009 5:10 am    Post subject: Reply with quote

cgordon wrote:
Quote:
craig, if you look at my first post in the this thread, I believe it makes mention of the 7's and does exactly what you did.


Norm: Yes you may be right. But you never mentioned ERs. And this is my contention. Solutions should relate to recognisable techniques such as Wings , ERs or URs - otherwise the solutions become convoluted and esoteric solutions that transend the enjoyment of the masses.

Craig,
the pattern I pointed out is a ER.
and is hardly convoluted.
its just happens to have two other names.
two string kite and multi-coloring

these techniques have been discussed in this forum many times over and I would argue that these discussions are indeed enjoyed by the masses many times over.
ha! Cool
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HiMom



Joined: 02 Mar 2009
Posts: 3

PostPosted: Thu Mar 26, 2009 11:23 am    Post subject: Re: One-step XYZ-wing did it for me Reply with quote

Marty R. wrote:
HiMom wrote:
XYZ-wing 34-345-35 in the corners eliminated the 3 in r9c1

Hi, HiMom,

Could you elaborate? I'm not seeing it.


Marty,
Simply put: I misread it and got lucky. Not a strategy I'd recommend, although its sometimes worked for me... Embarassed
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