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		ZeroAssoluto
 
 
  Joined: 05 Feb 2017 Posts: 1020 Location: Rimini, Italy
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				 Posted: Thu Jan 27, 2022 2:05 pm    Post subject: Jan 27 VH | 
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				Hi everyone, 
 
 
 	  | Code: | 	 		  
 
+-----------+----------+----------+
 
| 67  8  67 | 5  1 2   | 3  9 4   |
 
| 3   4  1  | 7  9 8   | 2  5 6   |
 
| 5   9  2  | 6  4 3   | 18 7 18  |
 
+-----------+----------+----------+
 
| 8   17 5  | 19 3 4   | 6  2 179 |
 
| 2   3  79 | 8  6 179 | 5  4 179 |
 
| 179 6  4  | 2  5 179 | 17 8 3   |
 
+-----------+----------+----------+
 
| 169 5  69 | 4  2 19  | 78 3 78  |
 
| 4   2  8  | 3  7 6   | 9  1 5   |
 
| 179 17 3  | 19 8 5   | 4  6 2   |
 
+-----------+----------+----------+
 
 | 	  
 
Play this puzzle online at the Daily Sudoku site
 
 
 	  | Quote: | 	 		  | Skyscraper with number 9 in r6c16,r9c14 and -9 in r4c4,r7c6 | 	  
 
 
Ciao Gianni | 
			 
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		dongrave
 
 
  Joined: 06 Mar 2014 Posts: 572
 
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				 Posted: Thu Jan 27, 2022 2:19 pm    Post subject:  | 
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				| I used the 17-9 XY-Wing with pivot at r4c2 (-9r5c6) which then opened up another 17-9 XY-Wing with pivot at r5c6 (-9r7c3). | 
			 
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		TomC
 
 
  Joined: 30 Oct 2020 Posts: 359 Location: Wales
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				 Posted: Thu Jan 27, 2022 4:14 pm    Post subject:  | 
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				Two steps for me
 
X wing on <1> in r49c24 gives -1 in r9c1 (and r4c9)
 
then XY wing <679> pivot r7c3 gives -7 in r1c1 | 
			 
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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Thu Jan 27, 2022 4:16 pm    Post subject:  | 
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				 	  | Code: | 	 		  
 
+-----------+----------+----------+ 
 
|67   8  67 | 5  1 2   | 3  9 4   | 
 
| 3   4  1  | 7  9 8   | 2  5 6   | 
 
| 5   9  2  | 6  4 3   | 18 7 18  | 
 
+-----------+----------+----------+ 
 
| 8   17 5  | 19 3 4   | 6  2 179 | 
 
| 2   3  79c| 8  6 179 | 5  4 179 | 
 
| 179b 6 4  | 2  5 179a| 17 8 3   | 
 
+-----------+----------+----------+ 
 
| 169 5 69d | 4  2 x19x| 78 3 78  | 
 
| 4   2  8  | 3  7 6   | 9  1 5   | 
 
| 179 17 3  | 19 8 5   | 4  6 2   |
 
+-----------+----------+----------+ 
 
 | 	  
 
 
Sorry for the scruffy graphics but Strong links (a-b-c-d) on 9's provide a similar result to Gianni but with a kite. r7c6 < > 9 | 
			 
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		TomC
 
 
  Joined: 30 Oct 2020 Posts: 359 Location: Wales
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				 Posted: Thu Jan 27, 2022 8:00 pm    Post subject:  | 
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				Again another similar result using the 9's
 
 
r5c9 <> 9 as then d=9, a=9, leaves no room for <9> in box 4 | 
			 
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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Thu Jan 27, 2022 8:47 pm    Post subject:  | 
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				| ….and drops two 9’s in column 9 ! | 
			 
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		TomC
 
 
  Joined: 30 Oct 2020 Posts: 359 Location: Wales
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				 Posted: Thu Jan 27, 2022 8:55 pm    Post subject:  | 
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				 	  | Mogulmeister wrote: | 	 		  | ….and drops two 9’s in column 9 ! | 	  
 
Not sure about this, do you mean c3? | 
			 
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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Thu Jan 27, 2022 9:21 pm    Post subject:  | 
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				So lets start with your 9 in r5c9
 
 
(17=9)r5c9-r5c3=r7c3-r9c1=r9c4-r4c5=(9-17)r4c9
 
 
Two 9's in column 9 so r5c9 < > 9 | 
			 
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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Thu Jan 27, 2022 9:34 pm    Post subject:  | 
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				In case you're a visual type (I am)
 
 
Green is true and red is false
 
 
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		TomC
 
 
  Joined: 30 Oct 2020 Posts: 359 Location: Wales
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				 Posted: Thu Jan 27, 2022 9:35 pm    Post subject:  | 
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				| Understand now, I just think if you drop a number from a column you remove it | 
			 
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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Thu Jan 27, 2022 9:35 pm    Post subject:  | 
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				| We were here before with Immp's puzzle too ? | 
			 
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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Thu Jan 27, 2022 9:40 pm    Post subject:  | 
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				 	  | TomC wrote: | 	 		  Again another similar result using the 9's
 
 
r5c9 <> 9 as then d=9, a=9, | 	  
 
 
and if I can complete your chain Tom..and r4c4 is < >9 and r4c9 is 9 ! | 
			 
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		TomC
 
 
  Joined: 30 Oct 2020 Posts: 359 Location: Wales
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				 Posted: Thu Jan 27, 2022 9:41 pm    Post subject:  | 
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				| If r5c9=9 then r4c4=9, x=9 , no <9> in c3 is where I thought you were | 
			 
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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Thu Jan 27, 2022 9:43 pm    Post subject:  | 
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				 	  | TomC wrote: | 	 		  | Understand now, I just think if you drop a number from a column you remove it | 	  
 
 
Think loops! All those contradiction loops that set off on their logical path and turn round to bite themselves on the àrse! | 
			 
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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Thu Jan 27, 2022 9:43 pm    Post subject:  | 
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				 	  | TomC wrote: | 	 		  | If r5c9=9 then r4c4=9, x=9 , no <9> in c3 is where I thought you were | 	  
 
 
Which is fair enough too ! | 
			 
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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Thu Jan 27, 2022 9:44 pm    Post subject:  | 
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				| The point is once something is wrong contradictions appear everywhere and in many forms. | 
			 
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		TomC
 
 
  Joined: 30 Oct 2020 Posts: 359 Location: Wales
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				 Posted: Thu Jan 27, 2022 9:48 pm    Post subject:  | 
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				| Exactly, it's the way I see 'em | 
			 
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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Thu Jan 27, 2022 9:50 pm    Post subject:  | 
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				| You are the Frank Carson of Sudoku! (even if he's the wrong type of Celt) | 
			 
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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Fri Jan 28, 2022 8:26 am    Post subject:  | 
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				 	  | Mogulmeister wrote: | 	 		  In case you're a visual type (I am)
 
 
Green is true and red is false
 
 
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The sequence of these loops is important. Above shows the initial move from r5c9 (=9) green  to r5c3 (< > 9) red which leads to two 9’s in col 9
 
 
Using the same strong links, look what happens when your first step from r5c9 (=9) is to r4c9 (< > 9). Apart from the start cell at r5c9, all the greens become reds (< > 9) and reds become green (=9). 
 
 
This then gives you two 9’s in row 5 ! Different contradiction but same result 
 
r5c9 < > 9. | 
			 
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		TomC
 
 
  Joined: 30 Oct 2020 Posts: 359 Location: Wales
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				 Posted: Fri Jan 28, 2022 10:11 am    Post subject:  | 
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				| There is only one way to describe this puzzle | 
			 
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