dailysudoku.com Forum Index dailysudoku.com
Discussion of Daily Sudoku puzzles
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Jun 20 VH

 
Post new topic   Reply to topic    dailysudoku.com Forum Index -> Daily Sudoku puzzles
View previous topic :: View next topic  
Author Message
ZeroAssoluto



Joined: 05 Feb 2017
Posts: 943
Location: Rimini, Italy
PostPosted: Sun Jun 20, 2021 9:34 am    Post subject: Jun 20 VH Reply with quote
Hi everyone,

Code:

+---------+-------+-----------+
| 9 4  5  | 1 7 3 | 6  2   8  |
| 7 3  8  | 6 2 4 | 9  1   5  |
| 6 1  2  | 5 8 9 | 37 347 47 |
+---------+-------+-----------+
| 3 89 6  | 4 5 7 | 1  89  2  |
| 1 78 4  | 2 9 6 | 57 578 3  |
| 5 2  79 | 8 3 1 | 4  79  6  |
+---------+-------+-----------+
| 2 79 1  | 3 4 5 | 8  6   79 |
| 8 6  39 | 7 1 2 | 35 345 49 |
| 4 5  37 | 9 6 8 | 2  37  1  |
+---------+-------+-----------+

Play this puzzle online at the Daily Sudoku site

Quote:
W-Wing 3,7 in r3c7,r9c8 SL with number 7 in r37c9 and -3 in r3c8,r8c7
or
XY-Wing 3,5,7 in r58c7,r9c8 and -7 in r56c8


Ciao Gianni
Back to top
View user's profile Send private message
TomC



Joined: 30 Oct 2020
Posts: 358
Location: Wales
PostPosted: Sun Jun 20, 2021 9:53 am    Post subject: Reply with quote
The 357 wing that Gianni describes can also be used to remove the 7 in r9c3 as this leads to no 7's in box 4
Back to top
View user's profile Send private message
Mogulmeister



Joined: 03 May 2007
Posts: 1151
PostPosted: Mon Jun 21, 2021 8:59 am    Post subject: Reply with quote
TomC wrote:
The 357 wing that Gianni describes can also be used to remove the 7 in r9c3 as this leads to no 7's in box 4.


Yes - this can be extended via the (79)r6c8 to (79)r6c3 to create a slightly longer xy-chain which means that one of the pincers at r6c3 or r9c8 must be 7 ==> -7 at r9c3 and r6c8.

A good illustration showing that underneath these wing structures lurk the building blocks or fundamental xy chains.


The 37 W Wing is an XY chain too. One of those pincers at r3c7 or r9c8 must be 3 ==> -3 at r8c7 and r3c8.

Here's the notation which shows all this.

If you plug in "not 3" eg 7 at r3c7 you still get 3 in r9c8

(3=7)r3c7-(7=4)r3c9-(4=9)r8c9-(9=7)r7c9-(7=3)r9c8

If you plug in "not 3" eg 7 at r9c8 you still get 3 in r3c7

(3=7)r9c8-(7=9)r7c9-(9=4)r8c9-(4=7)r3c9-(7=3)r3c7
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    dailysudoku.com Forum Index -> Daily Sudoku puzzles All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group