The New Sudoku Players' Forum

[GordonBermant]

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

[ab]

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

[m_b_metcalf]

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