This is a follow up to my "If 6 Was 9" puzzle. It is a bit trickier than the original but uses even more symmetry and has a much more elegant solve path.
Normal sudoku rules apply.
Digits within cages sum to either 6 or 9.
By rotating the grid through 180° each cage sum is also rotated such that 6 becomes 9. For example; the cage at r1c234 must have a different value to the cage at r9c678.
Additionally every 6 placed in the grid must be rotationally symmetrical to a 9.
Digits separated by a white dot are consecutive. Not all possible dots are given.
Lösungscode: row 6