# Sjudoku II - A greater challenge in the world where 9 is 7

This is more difficult instance of a puzzle posted here.

Rules similar to Sudoku applies:

• In each disk, the numbers 1,2,...7 should appear exactly once.

• No line may contain duplicate digits (note that there are lines in 3 directions).

Solution is unique, and can be found by using classical sudoku-strategies.

• This one also looks to be symmetric - are there any asymmetric solutions, I wonder?
– Deusovi
Nov 14, 2020 at 22:39
• What does asymmetric solutions mean in this context? I chose positions of hints in a symmetric manner, as this is common for sudokus. But note that the values are not symmetric Nov 14, 2020 at 22:45
• I mean that it appears that rotating it 180 degrees and permuting the digits gives you the same puzzle. The solution is going to be symmetric up to permuting the 7 digits: every 3 will be opposite a 1, every 4 will be opposite a 5, every 6 will be opposite a 7.
– Deusovi
Nov 14, 2020 at 22:48
• (And the same is true of 60-degree rotations, not just 180-degree. The permutation isn't a simple digit swap, but it appears that we could create a consistent permutation that would work -- which leads me to question whether all solutions are the same, just with permuted digits.)
– Deusovi
Nov 14, 2020 at 22:58
• @Deusovi Given the solution of a single disc, there only three ways to fill all of the remaining discs. Nov 15, 2020 at 16:38

Solution:

Steps:

I didn't find it very difficult. It's basically just normal Sudoku techniques.

However I don't really know how to describe my process...