| View previous topic :: View next topic | 
	
	
		| Author | Message | 
	
		| daj95376 
 
 
 Joined: 23 Aug 2008
 Posts: 3854
 
 
 | 
			
				|  Posted: Thu Apr 28, 2011 9:22 pm    Post subject: Puzzle 11/04/28: ~ (late) 4-cell XY-Chain |   |  
				| 
 |  
				|  	  | Code: |  	  | +-----------------------+ | 9 . 6 | . 8 5 | 7 2 . |
 | . . . | . . . | . . . |
 | 4 . . | . . 2 | 8 . . |
 |-------+-------+-------|
 | . . . | 1 4 7 | 2 9 . |
 | 5 . . | 9 . . | . . . |
 | 7 . 9 | 6 . 3 | . 8 . |
 |-------+-------+-------|
 | 8 . 7 | 5 . . | 6 . . |
 | 3 . . | 8 . 6 | . 7 . |
 | . . . | . . . | . . . |
 +-----------------------+
 
 | 
 Play this puzzle online at the Daily Sudoku site
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| daj95376 
 
 
 Joined: 23 Aug 2008
 Posts: 3854
 
 
 | 
			
				|  Posted: Fri Apr 29, 2011 5:57 pm    Post subject: |   |  
				| 
 |  
				| Note: This is the last "Moderate" puzzle containing a 4-cell XY-Chain in my solver's solution. I've deleted the others from my puzzles remaining to be posted. 
 Regards, Danny
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| Marty R. 
 
 
 Joined: 12 Feb 2006
 Posts: 5770
 Location: Rochester, NY, USA
 
 | 
			
				|  Posted: Sat Apr 30, 2011 5:00 am    Post subject: |   |  
				| 
 |  
				| No early or late four-cell chains for me. 
 M-Wing
 XY-Loop
 XYZ-Wing
 Medusa
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| peterj 
 
 
 Joined: 26 Mar 2010
 Posts: 974
 Location: London, UK
 
 | 
			
				|  Posted: Sat Apr 30, 2011 8:28 am    Post subject: |   |  
				| 
 |  
				| I couldn't find one either! This was my path... 
 I also tried playing the xyz-wing(49-1) but I still couldn't find a 4-cell xy-chain! So maybe they are not easy after all. 	  | Quote: |  	  | w-wing(14) (4=1)r6c9 - r1c9=r3c8 - (1=4)r7c8 ; r8c9<>4 xy-chain (1=3)r1c9 - (3=1)r1c2 - (1=4)r5c2 - (4=5)r8c2 - (5=4)r8c7 - (4=1)r7c8 ; r3c8<>1, r8c9<>1
 | 
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| tlanglet 
 
 
 Joined: 17 Oct 2007
 Posts: 2468
 Location: Northern California Foothills
 
 | 
			
				|  Posted: Sat Apr 30, 2011 2:27 pm    Post subject: |   |  
				| 
 |  
				| I found a one step AUR but not the "brass ring". 
 AUR(14)r68c79 external sis: r7c8=1,r8c2=4; r7c8=1
 (4)r8c2-(4=1)r5c2-r13c2=r3c3-r3c8=(1)r7c8;
 
 Ted
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| daj95376 
 
 
 Joined: 23 Aug 2008
 Posts: 3854
 
 
 | 
			
				|  Posted: Sat Apr 30, 2011 2:55 pm    Post subject: |   |  
				| 
 |  
				| I guess it takes the righ combination of earlier steps to reach the 4-cell XY-Chain. 
 
  	  | Code: |  	  | <35+1>  XYZ-Wing r3c3/r1c2+r3c8         <> 1    r3c2 <49+1>  XYZ-Wing r8c9/r7c8+r8c5         <> 1    r8c7
 
 c67   X-Wing                          <> 9    r2c59
 r38     X-Wing                          <> 9    r2c59
 
 r24c23  <38> UR Type 4.2243             <> 3    r2c23
 r23c24  <37> UR Type 4.2243             <> 3    r23c2
 
 +-----------------------------------------------------+
 |  9    13   6    |  4    8    5    |  7    2    13   |
 |  2    578  58   |  37   16   19   |  49   45   36   |
 |  4    57   13   |  37   69   2    |  8    15   69   |
 |-----------------+-----------------+-----------------|
 |  6    38   38   |  1    4    7    |  2    9    5    |
 |  5    14   14   |  9    2    8    |  3    6    7    |
 |  7    2    9    |  6    5    3    |  1    8    4    |
 |-----------------+-----------------+-----------------|
 |  8    9    7    |  5    3    14   |  6    14   2    |
 |  3    45   2    |  8    19   6    |  45   7    19   |
 |  1    6    45   |  2    7    49   |  459  3    8    |
 +-----------------------------------------------------+
 # 31 eliminations remain
 
 (5=8)r2c3 - (8=3)r4c3 - (3=1)r3c3 - (1=5)r3c8  =>  r2c8,r3c2<>5
 
 | 
 Of course, the BUG+2 => r2c3<>5 would probably be easier.
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		|  |