Logic Masters Deutschland e.V.

Normal Sudoku rules apply. A number next to an arrow outside the grid indicates the sum of the digits along the diagonal in the direction of the arrow; digits may repeat along these diagonals. Digits in the circled cells are equal to the sum of the digits along the corresponding arrow in the grid.

The first part of this puzzle is quite tricky, but it becomes easy towards the end; hope you enjoy it nonetheless :)

f-puzzles link