The New Sudoku Players' Forum

by **dukuso** » Sat Oct 15, 2005 3:16 pm

Rotational Sudoku
-----------------

for the lazy people; each clue multiplies by 4 :

symbols permute by (permutation in cycle-notation)
(1,2,3,4)(5)(6,7,8,9), when the grid is rotated.

Code: Select all: 1236..... 5642..... ...1..... ......... ......... ......... ......... ......... ......... rated easy

whenever cell C contains symbol s then C rotated by 90'
counter-clockwise contains symbol p(s) with
p(1)=2
p(2)=3
p(3)=4
p(4)=1
p(5)=5
p(6)=7
p(7)=8
p(8)=9
p(9)=6

so in the above example the 4 corners must be:

Code: Select all: 1.......4 ......... ......... ......... ......... ......... ......... ......... 2.......3

etc.

the other sudoku rules apply.

Can someone make a rotational sudoku with 9 different clues
or with 8 clues ?

-Guenter

by **Lardarse** » Sat Oct 15, 2005 6:26 pm

Not enough places to put the 5's, maybe? One of them must go in the centre, but where would the... Ok, I see how now...

But you're still forced to put the 5 in r5c5, and the puzzle is forced to be diagonal (aka Sudoku X).

The fact that the 5 is forced to be there means you don't have to provide it to the solver. Although you could make the rotation groups unknown. But you still can't only include 7 different numbers if you do this...

LA

by **dukuso** » Sat Oct 15, 2005 7:06 pm

Lardarse wrote:Not enough places to put the 5's, maybe? One of them must go in the centre, but where would the... Ok, I see how now...

But you're still forced to put the 5 in r5c5, and the puzzle is forced to be diagonal (aka Sudoku X).

The fact that the 5 is forced to be there means you don't have to provide it to the solver. Although you could make the rotation groups unknown. But you still can't only include 7 different numbers if you do this...

LA

there is a unique solution.
Yes, a 5 must be in the center.
No, the puzzle is not necessarily diagonal, although there can only
be one 5 in any of the two main diagonals and this 5 is in the center.
The other 8 fives are rotational symmetrically arranged.

Here is one with 9 different clues:

Code: Select all: 1235..... 69....... 7........ 8..4..... ......... ......... ......... ......... .........

by **Lardarse** » Mon Oct 17, 2005 2:00 am

Hmm...

Since one number implies a few others, maybe you could get away with only 6 clues...