Logic Masters Deutschland e.V.

Normal Sudoku rules apply.

Digital Root definition: The digital root of a number is the sum of its digits, repeated until the result is a single digit. E.g. the digital root of [478] is 4+7+8 = 19 => 1+9 = 10 => 1+0 = 1.

Lines within each 3x3 box are "Digital Root" lines. The digital root of each line is equal to the digit in one of the circles in the same box. Every line corresponds to a different circle in that box.
Note that line color or thickness is not relevant and is purely cosmetic. Lines may overlap, even over multiple cells, but are always clearly visible when they do.

Within the entire 9x9 grid, one digit appears on every line.

In any 3x3 box with more than one circle, the digital root of the circles together is 9.

Along a black dot, one of the digits is double the other. All black dot pairs within the puzzle have the same two digits in some order.

Digits separated by the white dot are consecutive.

Play on Sudokupad.

Solved 3x3 example:

In this example, the red line has a digital root of 6 (2+4 = 6), and the black line has a digital root of 7 (1+4+5+6 = 16, 1+6=7). Both 6 and 7 appear in the circles, and the three circles together have a digital root of 9 (5+6+7 = 18, 1+8=9). 4 is double 2, and 2 and 3 are consecutive.