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. Circles with numbers in them give some of the numbers in the adjacent cells.

Everything is mod 10. So a 6 might mean 6, or 16, or 26, etc. The blue lines are region sum lines. For each line, digits on the line have an equal sum N within each box it passes through. So if one segment sums to 16, the other segments might sum to 6, 16, 26, etc. N can be different for different lines.

Link to sudokupad

If you enjoy this puzzle, I also have 4 other mod 10 puzzles of varying difficulties, that you can find links to here.