Logic Masters Deutschland e.V.

Rules: Normal Sudoku rules apply. Put the digits 1 to 9 once each into every row, column and 3x3 box.
Dot: Digits on the black dot are in a 1:2 ratio.
Outside Clues: Clues outside the grid are both X-Sums and Russian Doll sums:
X-Sums: A clue outside the grid gives the sum of the first X digits from that direction where X is the digit next to the clue.
Russian Doll Sums: A clue N outside the grid indicates that in that row or column there exists two digits that sum to N such that the sum of the digits between them is also N.

Links:
SudokuPad: https://sudokupad.app/a9s79lh32k