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		| immpy 
 
 
 Joined: 06 May 2017
 Posts: 574
 
 
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				|  Posted: Sun Apr 03, 2022 5:36 pm    Post subject: VH+ 040322 |   |  
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				| Hello all, enjoy the puzzle. 
 
  	  | Code: |  	  | +-------+-------+-------+
 | . . 6 | . 2 . | 7 . 3 |
 | . . 8 | 5 . . | . . . |
 | 4 2 . | . . . | . . 6 |
 +-------+-------+-------+
 | . 5 . | . 3 2 | . . . |
 | 1 . . | 6 . 4 | . . 9 |
 | . . . | 7 9 . | . 6 . |
 +-------+-------+-------+
 | 8 . . | . . . | . 4 1 |
 | . . . | . . 5 | 6 . . |
 | 7 . 3 | . 4 . | 9 . . |
 +-------+-------+-------+
 
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 Play this puzzle online at the Daily Sudoku site
 
 cheers...immp
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		| dongrave 
 
 
 Joined: 06 Mar 2014
 Posts: 572
 
 
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				|  Posted: Mon Apr 04, 2022 3:55 pm    Post subject: |   |  
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				| Thanks for the puzzle immpy!  Here's the grid after basics: 
  	  | Code: |  	  | +-------------+------------------+------------------+ | 5   19   6  | 4     2    189   | 7      189   3   |
 | 39  37   8  | 5     167  1679  | 124    129   24  |
 | 4   2    17 | 1389  178  13789 | 158    1589  6   |
 +-------------+------------------+------------------+
 | 6   5    9  | 18    3    2     | 148    178   478 |
 | 1   378  27 | 6     5    4     | 238    238   9   |
 |g23 f38   4  | 7     9   e18    | 12358  6     258 |
 +-------------+------------------+------------------+
 | 8  i69   5  | 239   67   3679  | 23     4     1   |
 |h29  4   b12 | 1389 c18   5     | 6      378   78  |
 | 7  a16*  3  | 128   4   d168   | 9      258   258 |
 +-------------+------------------+------------------+
 
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 And then I used the following chain: (6*-1)r9c2=r8c3-(1=8)r8c5-(6*8=1)r9c6-(1=8)r6c6-(8=3)r6c2-(3=2)r6c1-(2=9)r8c1-(9=6)r7c2 contradiction => r9c2 <> 6; stte.
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		| Clement 
 
 
 Joined: 24 Apr 2006
 Posts: 1113
 Location: Dar es Salaam Tanzania
 
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				|  Posted: Thu Apr 07, 2022 1:26 pm    Post subject: VH + 040322 |   |  
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				|  	  | Code: |  	  | +-------------------+------------------------+------------------------+
 | 5      19      6  | 4        2       189   | 7         189      3   |
 |e39    d37      8  | 5      cb167   cb1679  | 124       129      24  |
 | 4      2       17 | 1389     178     13789 | 158       1589     6   |
 +-------------------+------------------------+------------------------+
 | 6      5       9  | 18       3       2     | 148       178      478 |
 | 1      378     27 | 6        5       4     | 238       238      9   |
 | 23     38      4  | 7        9       18    | 12358     6        258 |
 +-------------------+------------------------+------------------------+
 | 8    ga6-9     5  | 239     b67     b3679  | 23        4        1   |
 |f29     4       12 | 1389     18      5     | 6         378      78  |
 | 7      16      3  | 128      4       168   | 9         258      258 |
 +-------------------+------------------------+------------------------+
 
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 (6)r7c2 = Type 4 UR(67)r27c56 – (7)r2c56 = (7-3)r2c2 = (3-9)r2c1 = r8c1 – (9)r7c2 => - 9r7c2; stte
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		| Mogulmeister 
 
 
 Joined: 03 May 2007
 Posts: 1151
 
 
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				|  Posted: Fri Apr 08, 2022 2:22 pm    Post subject: |   |  
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				| Very nice Clement. I like the way that your loop causes then pirouettes into the UR and back round again. |  | 
	
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		| Clement 
 
 
 Joined: 24 Apr 2006
 Posts: 1113
 Location: Dar es Salaam Tanzania
 
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				|  Posted: Fri Apr 08, 2022 4:10 pm    Post subject: |   |  
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				| Thanks. The UR kept appearing but, took me time to realize that it was useful. 	  | Mogulmeister wrote: |  	  | Very nice Clement. I like the way that your loop causes then pirouettes into the UR and back round again. | 
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		| dongrave 
 
 
 Joined: 06 Mar 2014
 Posts: 572
 
 
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				|  Posted: Sat Apr 09, 2022 1:08 am    Post subject: |   |  
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				|  	  | Clement wrote: |  	  | Thanks. The UR kept appearing but, took me time to realize that it was useful. 	  | Mogulmeister wrote: |  	  | Very nice Clement. I like the way that your loop causes then pirouettes into the UR and back round again. | 
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 Clement!  Thanks to you I learned the 6 different types of UR's today!  Please keep on posting!
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		| Mogulmeister 
 
 
 Joined: 03 May 2007
 Posts: 1151
 
 
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				|  Posted: Tue Apr 12, 2022 10:00 am    Post subject: |   |  
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				| I started looking at this with a contradictory hat on and observed that if you said that r6c1 = 3 then all manner of bad things happen. Using Don's grid (and lettering) 
 r2c1 = 9  r1c2 = 1 then a = 6 (r9c2) and b = 1 (r8c3) so c = 8 (r8c5) and d < > 6
 
 at the same time
 
 f = 8 (r6c2) and e = 1 (r6c6) and d also < > 1
 
 So
  c = 8 and d = 8 and we now have two 8's in box 8  impossibility so r6c1 < > 3 and puzzle solved. |  | 
	
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		| Pat 
 
 
 Joined: 23 Feb 2010
 Posts: 207
 
 
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				|  Posted: Thu Apr 14, 2022 5:22 am    Post subject: |   |  
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				|  	  | Code: |  	  | +-------------+------------------+------------------+ | 5   19   6  | 4     2    189   | 7      189   3   |
 | 39  37   8  | 5     167  1679  | 124    129   24  |
 | 4   2    17 | 1389  178  13789 | 158    1589  6   |
 +-------------+------------------+------------------+
 | 6   5    9  | 18    3    2     | 148    178   478 |
 | 1   378  27 | 6     5    4     | 238    238   9   |
 | 23  38   4  | 7     9    18    | 12358  6     258 |
 +-------------+------------------+------------------+
 | 8   69   5  | 239   67   3679  | 23     4     1   |
 | 29  4    12 | 1389  18   5     | 6      378   78  |
 | 7   16   3  | 128   4    168   | 9      258   258 |
 +-------------+------------------+------------------+
 
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 yes, seems it needs split attention:
 if r8c1 = 2
 then
 r8c3 = 1
 
 then two things happen:
 
 combined → r9c6 = 1, r6c6 = 8, r6c2 = 3, r6c1 = 2, conflict in c1
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		| Mogulmeister 
 
 
 Joined: 03 May 2007
 Posts: 1151
 
 
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				|  Posted: Sun Apr 17, 2022 11:42 am    Post subject: |   |  
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				| Absolutely Pat - when you make r6c1 = 3 which makes r8c1 = 2 as you say, we need to recognise this bifurcation or split. 
 To put a nice bow on all this contradiction and sorry about the graphics*, I am going to have a go at this in Eureka:
 
 
  	  | Code: |  	  | 2r8c1-(2=1)r8c3-(1=8)r8c5-(68=1)r9c6-(1=8)r6c6-(8=3)r6c2-(3=2)r6c1-(2)r8c1; r8c1 < > 2; stte |               ^
 V               |
 (1=6)r9c2-----------
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 If you plug 2 into r8c1 the loop removes it showing that it can not be 2. A tributary forms at r8c3 and then rejoins the main river at r9c6.
 
 *Diagram only works in full screen mode on a PC or Mac!
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