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 

A "Turbot Fish" example

 
Post new topic   Reply to topic    dailysudoku.com Forum Index -> Other puzzles
View previous topic :: View next topic  
Author Message
David Bryant



Joined: 29 Jul 2005
Posts: 559
Location: Denver, Colorado

PostPosted: Sun Nov 06, 2005 6:10 pm    Post subject: A "Turbot Fish" example Reply with quote

This puzzle appeared in the Rocky Mountain News on Saturday, November 5. It contains a good example of the "turbot fish" formation.
Code:
 5 . .  . . 4  . . 2
 3 . .  . . .  . 6 .
 . . 8  5 . .  4 . .

 8 . .  . 9 .  6 . 4
 . . .  1 8 6  . . .
 1 . 3  . 2 .  . . 5

 . . 4  . . 9  2 . .
 . 1 .  . . .  . . 6
 6 . .  2 . .  . . 7

After a series of mostly routine moves one arrives at this position.
Code:
   5     7/9     6     8/9   *1/3*    4    1/3/8  3/7/8    2
   3      4      1     8/9     7      2      5      6     8/9
   2     7/9     8      5      6    *1/3*    4     3/7   *1/9*

   8      2      7      3      9      5      6      1      4
   4      5      9      1      8      6      7      2      3
   1      6      3      4      2      7     8/9    8/9     5

   7     3/8     4      6   *1/3/5*   9      2    3/5/8  *1/8*
   9      1      2      7     4/5    3/8    3/8    4/5     6
   6     3/8     5      2    1/3/4  1/3/8    .      .      7

The key to further progress lies in the chain of 1/~1 cells marked with "*"s in this grid. We can see that r7c5 cannot be a "1" because if it is a contradiction cannot be avoided. So the "1" in row 7 must appear at r7c9, and the rest of the puzzle is easily resolved.

This formation is a type of "turbot fish," which has been well analyzed by "Nick70" on the sudoku.com forum. dcb
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    dailysudoku.com Forum Index -> Other 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