Significance of symmetry?

Everything about Sudoku that doesn't fit in one of the other sections

Significance of symmetry?

Postby GordonBermant » Tue Dec 11, 2007 7:03 pm

I'm new to the game, and have noticed that some puzzles have a symmetry in their opening configurations and some don't. I'm guessing this has to do with how they are constructed, to ensure uniqueness or something, but I am guessing. Can someone explain please?

Thanks,

Gordon Bermant
GordonBermant
 
Posts: 1
Joined: 11 December 2007

Postby ab » Tue Dec 11, 2007 7:35 pm

Puzzles with symmetry look prettier, that's about the long and short of it. Symmetric puzzles may not be minimal, but hopefully if they're not, the redundant clues do not affect their difficulty. There is of course another possibility, that the setter is unaware of some more advanced solving techniques that make a particular clue redundant.
ab
ab
 
Posts: 451
Joined: 06 September 2005

Re: Significance of symmetry?

Postby m_b_metcalf » Tue Dec 11, 2007 7:36 pm

GordonBermant wrote:I'm new to the game, and have noticed that some puzzles have a symmetry in their opening configurations and some don't. I'm guessing this has to do with how they are constructed, to ensure uniqueness or something, but I am guessing. Can someone explain please?


It is purely for aesthetic reasons. Many puzzles copy the standard rotational symmetry of crosswords. All sudokus have a unique solution. Symmetry simply makes it harder to make a minimal puzzle, one in which no clue can be removed without sacrificing uniqueness.

HTH

Mike Metcalf
User avatar
m_b_metcalf
2017 Supporter
 
Posts: 13577
Joined: 15 May 2006
Location: Berlin


Return to General