Logic Masters Deutschland e.V.

1. Normal sudoku rules apply. Each row, column, and box must be filled with the digits 1-9 exactly once.

2. Digits in columns 1, 5, and 9 determine the positions of digits 1, 5, and 9 in each of their respective rows (eg. if R2C1 is a 7, then R2C7 is a 1).

3. Rotational sums of 10 applies to ONLY columns 1, 5, and 9. If the board is rotated 180 degrees, all pairs of digits on columns 1, 5, and 9 sum to 10 (eg. if R3C1 is a 5, then R7C9 is a 5).

4. Quadruple: Digits in circles must appear TWICE in the four surrounding squares. All circles have been given (negative constraint applies, like a restricted anti-king).

Solve on Sudokupad here!

Feedback is appreciated!