Logic Masters Deutschland e.V.

This is my first attempt at a Sudoku. I have no experience in judging the difficulty, but I expect this to be hard.

Fill the grid with digits 1 to 9, so that each digit occurs exactly once in every row, every column and every 3x3 box. Numbers given at the corner of each dashed cage indicate the sum of all digits inside the cage. No digit may be repeated within a cage.