The New Sudoku Players' Forum

[tso]

The pattern of the clues in this hard Sudoku has 180 rotational symmetry but the grid has a whole is completely asymmetrical:

Code: Select all

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


Here are three more puzzles with the same mask, increasingly easier:

13...857.7....4.2.694..2......47.......18......1..983.5.7....9.283...61..........
67...124.4....8.3.892..6......48.......15......1..378.3.4....2.958...61..........
51...728.9....4.3.382..6......23.......61......3..865.7.6....4.895...71..........



[EDITED to delete factual errors]
Might there be found a 17 cell which has all of it's clues in an 8x8 area with diagonal mirror symmetry, similar to the following 23 clue puzzle? (Rotational symmetry is impossible in an 8x8 area with an odd number of clues, as is any of the other mirror symmetries.)

Code: Select all

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

[Red Ed]

I *believe* no one has found 17 cell Sudoku with symmetry

Here are 10 examples.

[tso]

Don't know how I missed that. I've edited the original post.