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Aug 23 VH

 
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ZeroAssoluto



Joined: 05 Feb 2017
Posts: 868
Location: Rimini, Italy

PostPosted: Tue Aug 22, 2017 10:21 pm    Post subject: Aug 23 VH Reply with quote

Hi everyone,

Code:

+-----------+------------+--------------+
| 146 12  5 | 67 9   167 | 3  8    1246 |
| 146 8   7 | 5  3   2   | 16 146  9    |
| 169 129 3 | 4  168 168 | 7  5    126  |
+-----------+------------+--------------+
| 3   5   2 | 9  4   16  | 8  16   7    |
| 7   4   9 | 8  16  3   | 16 2    5    |
| 8   6   1 | 2  7   5   | 9  34   34   |
+-----------+------------+--------------+
| 5   17  6 | 3  2   9   | 4  17   8    |
| 2   79  4 | 1  68  678 | 5  3679 36   |
| 19  3   8 | 67 5   4   | 2  1679 16   |
+-----------+------------+--------------+

Play this puzzle online at the Daily Sudoku site

Quote:
Sashimi X-Wing with number 1 in r29c19 + r1c9 and -1 in r2c7


Ciao Gianni
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Marty R.



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

PostPosted: Wed Aug 23, 2017 5:11 am    Post subject: Re: Aug 23 VH Reply with quote

ZeroAssoluto wrote:
Hi everyone,

Code:

+-----------+------------+--------------+
| 146 12  5 | 67 9   167 | 3  8    1246 |
| 146 8   7 | 5  3   2   | 16 146  9    |
| 169 129 3 | 4  168 168 | 7  5    126  |
+-----------+------------+--------------+
| 3   5   2 | 9  4   16  | 8  16   7    |
| 7   4   9 | 8  16  3   | 16 2    5    |
| 8   6   1 | 2  7   5   | 9  34   34   |
+-----------+------------+--------------+
| 5   17  6 | 3  2   9   | 4  17   8    |
| 2   79  4 | 1  68  678 | 5  3679 36   |
| 19  3   8 | 67 5   4   | 2  1679 16   |
+-----------+------------+--------------+

Play this puzzle online at the Daily Sudoku site

Quote:
Sashimi X-Wing with number 1 in r29c19 + r1c9 and -1 in r2c7


Ciao Gianni


Gianni,

I'm very confused, which is nothing new. In r2 I see 1s in c178; in r9 I see 1s in c189. Am I misinterpreting what you wrote?
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JC Van Hay



Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium

PostPosted: Wed Aug 23, 2017 5:51 am    Post subject: Reply with quote

Only 1r7c2 [1r3c9] belongs [doesn't belong] to all the solutions of the 1s; stte

Interpretation :
Grouped Kite {1R2, 1C9} -> -1r9c1; r7c2=1 and stte
[Skyscraper {1C57} -> -1r3c9]
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ZeroAssoluto



Joined: 05 Feb 2017
Posts: 868
Location: Rimini, Italy

PostPosted: Wed Aug 23, 2017 6:52 am    Post subject: Reply with quote

Hi Marty,

I make confusion
In the situation of the scheme I used an XY-Wing 1,6,7 in r7c8, r9c49 and -7 in r9c8;
which brings me to this situation where I used the Sashimi X-Wing

Code:

+---------+---------+-----------+
| 4  12 5 | 6 9  7  | 3  8   12 |
| 16 8  7 | 5 3  2  | 16 4   9  |
| 69 29 3 | 4 18 18 | 7  5   26 |
+---------+---------+-----------+
| 3  5  2 | 9 4  16 | 8  16  7  |
| 7  4  9 | 8 16 3  | 16 2   5  |
| 8  6  1 | 2 7  5  | 9  3   4  |
+---------+---------+-----------+
| 5  17 6 | 3 2  9  | 4  17  8  |
| 2  79 4 | 1 68 68 | 5  79  3  |
| 19 3  8 | 7 5  4  | 2  169 16 |
+---------+---------+-----------+

Play this puzzle online at the Daily Sudoku site

excuse me
Ciao Gianni
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Clement



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

PostPosted: Wed Aug 23, 2017 7:43 am    Post subject: Aug 23 VH Reply with quote

Code:

+-----------+-----------+--------------+
| 146 12  5 | 67 9  167 | 3  8    1246 |
| 146 8   7 | 5  3  2   | 16 146  9    |
| 169 129 3 | 4  16 8   | 7  5    12   |
+-----------+-----------+--------------+
| 3   5   2 | 9  4  16  | 8  16   7    |
| 7   4   9 | 8  16 3   | 16 2    5    |
| 8   6   1 | 2  7  5   | 9  34   34   |
+-----------+-----------+--------------+
| 5   17  6 | 3  2  9   | 4  17   8    |
| 2   79  4 | 1  8  67  | 5  3679 36   |
| 19  3   8 | 67 5  4   | 2  169-7 16  |
+-----------+-----------+--------------+

XY-Wing 16-7 pivoted in r9c9 solves it, 7 is strongly linked in r9
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JC Van Hay



Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium

PostPosted: Wed Aug 23, 2017 8:30 am    Post subject: Reply with quote

r3c8=r8c5=8 Rolling Eyes
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hughwill



Joined: 05 Apr 2010
Posts: 422
Location: Birmingham UK

PostPosted: Wed Aug 23, 2017 9:09 am    Post subject: Re: Aug 23 VH Reply with quote

Clement wrote:
Code:

+-----------+-----------+--------------+
| 146 12  5 | 67 9  167 | 3  8    1246 |
| 146 8   7 | 5  3  2   | 16 146  9    |
| 169 129 3 | 4  16 8   | 7  5    12   |
+-----------+-----------+--------------+
| 3   5   2 | 9  4  16  | 8  16   7    |
| 7   4   9 | 8  16 3   | 16 2    5    |
| 8   6   1 | 2  7  5   | 9  34   34   |
+-----------+-----------+--------------+
| 5   17  6 | 3  2  9   | 4  17   8    |
| 2   79  4 | 1  8  67  | 5  3679 36   |
| 19  3   8 | 67 5  4   | 2  169-7 16  |
+-----------+-----------+--------------+

XY-Wing 16-7 pivoted in r9c9 solves it, 7 is strongly linked in r9



I'm confused as to how r3c9 doesn't have a possible 6 in this diagram. My
basics done diagram was the same as Gianni's first. I needed a second
19-6 XY wing pivot 9c1 to set the puzzle (-6r3c9) (as in Gianni's 2nd
diagram).

Hugh
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Ajò Dimonios



Joined: 01 May 2017
Posts: 339
Location: Sassari Italy

PostPosted: Wed Aug 23, 2017 10:56 am    Post subject: Reply with quote

Hi everyone

[(1)R7C8-(1)R2C8; (1)R7C8-(1)R4C8=(1)R5C7-(1)R2C6 and (1)R7C8-(1)R7C2=(1)R9C1-(1)R2C2]=>contradiction no candidate 1 in line 2=>-1R7C8=>solution stte.

or -7R7C2 ; R7C2=7 is biunivoca with R7C8=1

or -1R9C1; R9C1=1 is biunivoca with R7C8=1

or -9R9C8; R9C8=9 is biunivoca con R7C8=1

Ciao a Tutti
Paolo
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the_lock_man



Joined: 18 Dec 2012
Posts: 40
Location: Portsmarfff, UK

PostPosted: Wed Aug 23, 2017 11:40 am    Post subject: Re: Aug 23 VH Reply with quote

Clement wrote:
Code:

+-----------+-----------+--------------+
| 146 12  5 | 67 9  167 | 3  8    1246 |
| 146 8   7 | 5  3  2   | 16 146  9    |
| 169 129 3 | 4  16 8   | 7  5    12   |
+-----------+-----------+--------------+
| 3   5   2 | 9  4  16  | 8  16   7    |
| 7   4   9 | 8  16 3   | 16 2    5    |
| 8   6   1 | 2  7  5   | 9  34   34   |
+-----------+-----------+--------------+
| 5   17  6 | 3  2  9   | 4  17   8    |
| 2   79  4 | 1  8  67  | 5  3679 36   |
| 19  3   8 | 67 5  4   | 2  169-7 16  |
+-----------+-----------+--------------+

XY-Wing 16-7 pivoted in r9c9 solves it, 7 is strongly linked in r9


I got that, then a few basic moves, but then needed a W-Wing on 16, boxes 1 & 9 (the basics had removed the 4 from R2C1) to make R9C1<>1.

Not sure what I missed to make it a 1-stepper.

Now, off to do a squiggly!
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Marty R.



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

PostPosted: Wed Aug 23, 2017 12:34 pm    Post subject: Reply with quote

Quote:
I needed a second
19-6 XY wing pivot 9c1 to set the puzzle (-6r3c9) (as in Gianni's 2nd
diagram).


Me too.
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Ajò Dimonios



Joined: 01 May 2017
Posts: 339
Location: Sassari Italy

PostPosted: Wed Aug 23, 2017 1:33 pm    Post subject: Reply with quote

Hi everyone

Code:

+-----------+------------+--------------+
| 146 12  5 | 67 9   167 | 3  8    1246 |
| 146 8   7 | 5  3   2   | 16 146  9    |
| 169 129 3 | 4  168 168 | 7  5    126  |
+-----------+------------+--------------+
| 3   5   2 | 9  4   16  | 8  16   7    |
| 7   4   9 | 8  16  3   | 16 2    5    |
| 8   6   1 | 2  7   5   | 9  34   34   |
+-----------+------------+--------------+
| 5   17  6 | 3  2   9   | 4  17   8    |
| 2   79  4 | 1  68  678 | 5  3679 36   |
| 19  3   8 | 67 5   4   | 2  1679 16   |
+-----------+------------+--------------+

Play this puzzle online at the Daily Sudoku site




Another solution with one step after basics.

[(1)R2C7-(1)(R2C8,R3C9,R1C9) and (1)R2C7-(1)R5C7=(1)R4C8-(1)R79C8=(1)R9C9-(1=9)R9C1-(9)R3C1=(9-2)R3C2=(2)R3C9-(2)R1C9=NP(46)(R1C9,R2C8)-(6)R3C9]=>contradiction R3C9=Ø=>-(1)R2C7=>stte.

Ciao a Tutti
Paolo
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Earl



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

PostPosted: Wed Aug 23, 2017 1:45 pm    Post subject: Aug 23 VH Reply with quote

I needed two steps:

167 xywing @r9c9, -7r9c8
skyscraper of 1 (r1,7), -1r9c9

Early Earl
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dongrave



Joined: 06 Mar 2014
Posts: 563

PostPosted: Wed Aug 23, 2017 10:02 pm    Post subject: Reply with quote

I had to use 2 'standard' moves. My first move (which Clement said solves it!) was the 16-7 XY Wing with pivot at r9c9 and then a 19-6 XY Wing with pivot at r9c1 which solved it! I have to go back and see if the first XY Wing solves it like Clement said. (what did i miss? ugh.)

Update: I see that Hugh and I had the same solution. I think it requires the XY Wing if you only use standard moves.
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Ajò Dimonios



Joined: 01 May 2017
Posts: 339
Location: Sassari Italy

PostPosted: Thu Aug 24, 2017 9:26 am    Post subject: Reply with quote

Hi everyone

In the R9C8 cell, only -9R9C8 produces a one-step solution. As I said in a previous post, 9 in R9C8 is biunivoca with 1 in R7C8 (another solution in one step). Virtually when 9 in R9C8 is true even 1 in R7C8 is true and when 1 in R7C8 is true even 9 in R9C8 is true. The consequence of this is that if you prove that 1 in R7C8 is fake (as I wrote in my previous post) even 9 in R9C8 is false.

Ciao a Tutti

Paolo
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Clement



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

PostPosted: Thu Aug 24, 2017 3:42 pm    Post subject: Reply with quote

dongrave wrote:
I had to use 2 'standard' moves. My first move (which Clement said solves it!) was the 16-7 XY Wing with pivot at r9c9 and then a 19-6 XY Wing with pivot at r9c1 which solved it! I have to go back and see if the first XY Wing solves it like Clement said. (what did i miss? ugh.)

Update: I see that Hugh and I had the same solution. I think it requires the XY Wing if you only use standard moves.
You didn't miss anything, I accidentally omitted the 6 in r3c9 which led me to a single stepper solution, it needed one more step as you have done and all others. I apologize for the inconvenience it may have caused.
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the_lock_man



Joined: 18 Dec 2012
Posts: 40
Location: Portsmarfff, UK

PostPosted: Fri Aug 25, 2017 11:20 am    Post subject: Reply with quote

Clement wrote:
dongrave wrote:
I had to use 2 'standard' moves. My first move (which Clement said solves it!) was the 16-7 XY Wing with pivot at r9c9 and then a 19-6 XY Wing with pivot at r9c1 which solved it! I have to go back and see if the first XY Wing solves it like Clement said. (what did i miss? ugh.)

Update: I see that Hugh and I had the same solution. I think it requires the XY Wing if you only use standard moves.
You didn't miss anything, I accidentally omitted the 6 in r3c9 which led me to a single stepper solution, it needed one more step as you have done and all others. I apologize for the inconvenience it may have caused.


We'll forgive you.
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