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May 15 VH

 
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Marty R.



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

PostPosted: Fri May 15, 2009 12:39 am    Post subject: May 15 VH Reply with quote

I feel like getting Earl mad, so I'm starting the thread before him. Laughing

I did it twice, just to make sure of my original solution.

Quote:
It's a zero-stepper
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Louise56



Joined: 21 Sep 2005
Posts: 94
Location: El Cajon, California USA

PostPosted: Fri May 15, 2009 12:55 am    Post subject: Reply with quote

I did it once but needed a step, I'll try it again to see if I can keep up with Marty Smile
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themarsman



Joined: 17 Jun 2007
Posts: 7

PostPosted: Fri May 15, 2009 4:51 am    Post subject: Reply with quote

I was also able to solve it using no advanced techniques. Not a very hard by any measure
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swando



Joined: 09 Mar 2009
Posts: 17
Location: Surrey, BC. Canada

PostPosted: Fri May 15, 2009 9:27 am    Post subject: Reply with quote

I don't know if it was needed but I spotted an xy wing on 239 and that solved it quite easily
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Fri May 15, 2009 11:57 am    Post subject: Reply with quote

Yes, no advanced steps required. The hardest step is to notice the <39> pair, after you have noticed the easy <28> pair.

Keith


Last edited by keith on Fri May 15, 2009 9:20 pm; edited 2 times in total
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cgordon



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

PostPosted: Fri May 15, 2009 1:22 pm    Post subject: Reply with quote

Funny that! I used an ER on 9 which was very easy to spot and then read that no VH steps were required. So I did it again VH-less and it took me much longer. This suggests that one step VHs are easier than zero-step VHs. But then you can't have zero-step VHs. It's all so confusing!
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giadich



Joined: 15 May 2009
Posts: 3

PostPosted: Fri May 15, 2009 8:08 pm    Post subject: Reply with quote

Just curious!
Has anyone ever solved Sudoku puzzle by using just paper printout and pen? and please do not write out combo numbers on the puzzle. It looks too messy
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Fri May 15, 2009 8:20 pm    Post subject: Reply with quote

giadich wrote:
Just curious!
Has anyone ever solved Sudoku puzzle by using just paper printout and pen? and please do not write out combo numbers on the puzzle. It looks too messy

I'd like to think most solvers start this way.
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giadich



Joined: 15 May 2009
Posts: 3

PostPosted: Fri May 15, 2009 8:44 pm    Post subject: Reply with quote

storm_norm wrote:
giadich wrote:
Just curious!
Has anyone ever solved Sudoku puzzle by using just paper printout and pen? and please do not write out combo numbers on the puzzle. It looks too messy

I'd like to think most solvers start this way.


Agree! It is a true sudoku solver.
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Kdelle



Joined: 20 Mar 2008
Posts: 59
Location: Hudson, NH

PostPosted: Fri May 15, 2009 9:21 pm    Post subject: Reply with quote

giadich wrote:
Just curious!
Has anyone ever solved Sudoku puzzle by using just paper printout and pen? and please do not write out combo numbers on the puzzle. It looks too messy


I've often thought that our different "approaches" would make for an interesting discussion. When I first found this site I was very appreciative of the "sweep" feature....but now I rarely use it because I found that I wasn't really "looking" at the puzzle, but rather looking at the"possibilies". So a unique possibility jumped right out at me. But I find I more enjoy pencil (NOT pen) and paper.

Edit: If I make a mistake, though.....It's a sweep for me!
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Mike S



Joined: 15 May 2009
Posts: 6

PostPosted: Fri May 15, 2009 11:12 pm    Post subject: 39, 239 Reply with quote

I'm having trouble spotting the <39> pair
and the <239> XY Wing. Can someone
point me in the right direction.

Thanks for your help.
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Fri May 15, 2009 11:35 pm    Post subject: Reply with quote

Mike,

Basics should get you to here. This is not necessarily that easy!

Code:
+-------------------+-------------------+-------------------+
| 6     1     7     | 9     8     23    | 4     5     23    |
| 23589 289   258   | 4     6     7     | 1     28    2389  |
| 2389  2489  248   | 5     1     23    | 39    7     6     |
+-------------------+-------------------+-------------------+
| 28    3     248   | 1     24    5     | 6     9     7     |
| 7     24    6     | 3     24    9     | 8     1     5     |
| 1     5     9     | 8     7     6     | 2     3     4     |
+-------------------+-------------------+-------------------+
| 4     29    1     | 7     5     8     | 39    6     239   |
| 589   6     58    | 2     3     1     | 7     4     89    |
| 28    7     3     | 6     9     4     | 5     28    1     |
+-------------------+-------------------+-------------------+

The <28> pair is in C1. Then, the <39> pair is in R3:
Code:
+----------------+----------------+----------------+
| 6    1    7    | 9    8    23   | 4    5    23   |
| 359  289  258  | 4    6    7    | 1    28   2389 |
| 39   2489 248  | 5    1    23   | 39   7    6    |
+----------------+----------------+----------------+
| 28   3    248  | 1    24   5    | 6    9    7    |
| 7    24   6    | 3    24   9    | 8    1    5    |
| 1    5    9    | 8    7    6    | 2    3    4    |
+----------------+----------------+----------------+
| 4    29   1    | 7    5    8    | 39   6    239  |
| 59   6    58   | 2    3    1    | 7    4    89   |
| 28   7    3    | 6    9    4    | 5    28   1    |
+----------------+----------------+----------------+


I do not see that there is any <239> wing, if you first exhaust the singles on the way to the first grid I posted above.

Keith
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Mike S



Joined: 15 May 2009
Posts: 6

PostPosted: Fri May 15, 2009 11:55 pm    Post subject: Reply with quote

Thanks for the info. I was pretty far along when I got stuck:

Code:

+------------+--------+------------+
| 6    1  7  | 9 8 23 | 4  5  23   |
| 2359 29 25 | 4 6 7  | 1  28 2389 |
| 239  8  4  | 5 1 23 | 39 7  6    |
+------------+--------+------------+
| 28   3  28 | 1 4 5  | 6  9  7    |
| 7    4  6  | 3 2 9  | 8  1  5    |
| 1    5  9  | 8 7 6  | 2  3  4    |
+------------+--------+------------+
| 4    29 1  | 7 5 8  | 39 6  239  |
| 589  6  58 | 2 3 1  | 7  4  89   |
| 28   7  3  | 6 9 4  | 5  28 1    |
+------------+--------+------------+


I can't believe I missed a naked pair, <28>, in column 1.
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Clement



Joined: 24 Apr 2006
Posts: 1110
Location: Dar es Salaam Tanzania

PostPosted: Sat May 16, 2009 4:38 am    Post subject: Daily Sudoku: Fri 15-May-2009 VH Reply with quote

XY-Wing <258> with pivot <58> in r8c3 and pincers <28>r8c1 and <25> r2c3 eliminating the 2's in BOX 1 c1 solves the puzzle.
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swando



Joined: 09 Mar 2009
Posts: 17
Location: Surrey, BC. Canada

PostPosted: Sat May 16, 2009 7:08 am    Post subject: Re: 39, 239 Reply with quote

Mike S wrote:
I'm having trouble spotting the <39> pair
and the <239> XY Wing. Can someone
point me in the right direction.

Thanks for your help.


----------------------------------------

This is where I got with the basics:
[code]
+----------------+---------+------------+
| 236 1 7 | 9 8 23 | 4 5 23 |
| 23589 289 258 | 4 6 7 | 1 28 2389 |
| 2389 2489 248 | 5 1 23 | 39 7 6 |
+----------------+---------+------------+
| 28 3 248 | 1 24 5 | 6 9 7 |
| 7 24 6 | 3 24 9 | 8 1 5 |
| 1 5 9 | 8 7 6 | 2 3 4 |
+----------------+---------+------------+
| 4 29 1 | 7 5 8 | 39 6 239 |
| 5689 689 58 | 2 3 1 | 7 4 89 |
| 28 7 3 | 6 9 4 | 5 28 1 |
+----------------+---------+------------+

The xyz was 29 239 and 23 and that solved it for me. I spot these easier
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Wendy W



Joined: 04 Feb 2008
Posts: 144

PostPosted: Sat May 16, 2009 3:42 pm    Post subject: Reply with quote

Yep, I still use paper and pencil (and eraser). I spend most of the day on the computer so it's a nice break to sit on the sofa.
Re: yesterday's puzzle -- I didn't need any advanced techniques either -- it just fell apart with those pairs.
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George Woods



Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK

PostPosted: Sat May 16, 2009 9:23 pm    Post subject: an ER soluion alos works Reply with quote

If you take the Mike S grid. there is an ER in 2 in in box7 with a strong link in 2 s in col 7 so r2c2 cannot be 2 --- and hence a solution
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