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!
Solution code: Row 4 (read from left to right)
today, 03:43 by LARSPARIS
I have had to guess somtimes, but there is surement a way without guessing
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