Logic Masters Deutschland e.V.

Normal Sudoku rules apply (each row, column, and given 3x3 box must contain the digits 1 to 9). Cells with a shaded circle are odd digits; cells with a square are even. And everything is mod 10. So a 6 might mean 6, or 16, or 26, etc.

The following variants are all subject to the mod 10 rule. Digits along an arrow must sum to the number in the circle - e.g. if a 4 is in the circle, the digits along the arrow might sum to 4, 14, 24, etc. Digits in a cage must add to the sum in the top left corner - e.g. if the number in the corner is 0, the digits might sum to 10, 20, 30, etc. Digits on either side of a black dot must have a ratio of 1:2 (one is double the other) - 6 can be paired with 2 (6x2=12), 3 (3x2=6), or 8 (8x2=16).

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