LMI July Sudoku Contest 'Classic Look-Alikes'

[debmohanty]

Hi,
I checked the instruction booklet and have a question to one special kind of Sudoku.
It is called Symmetric unequal sudoku.
What does it mean exactly: Cells that are 180° symmetric to each other cannot have same digits.
Can you give an example which cells are 180° symmetric in a diagram.

Thanks and regards
Fried

Hi,
It is basically you rotate the Sudoku 180° keeping the center cell fixed.
R1C1 is 180° symmetric to R9C9. R3C3 180° symmetric to R7C7, R1C6 180° symmetric to R8C4. So as per the rules, R1C1 can never have the same digit as R9C9. R3C3 can never have the same digit as R7C7, similarly R1C6 can never have the same digit as R8C4, so on ...

Mathematically, RnCn can never have the same digit as R[10-n]C[10-n]

Hope it is clear.