Logic Masters Deutschland e.V.

• Standard 6x6 sudoku rules apply (digits 1 to 6);
• Digits connected by a "V" symbol sum to 5 (not all V's are given)
• Waterfall rules: a ruleset I've only seen by (without much success by XDuncan, in his Waterfall Sudoku (id: 00064L).

Waterfall rules: the numbers above the puzzle represent the value of individual streams, whenever a stream enters a cell it either keeps flowing if the value of the cell is greater than that of the stream, it "sinks" (stops on that cell) if the cell value and stream value are equal or is split in two if the value of the cell is smaller than that of the stream.
When the stream is split it first loses the value of the cell it encountered and then continues flowing in the two cells below the visited one one the side (diagonally adjacent) with half of the value in both streams. A stream must have an integer value (i.e. when a stream is split there may not be "half" values).
At the bottom of the puzzle, all three streams keep flowing out of the board downwards and the streams at those points have the indicated values.
Two streams flowing into the same cell unite in a sigle stream that has the sum of their values.

The puzzle is themed around norwegian waterfalls and was originally inspired by some specific ones in the fjord of Geiranger. After noticing how some (basic) algebra is involved in the puzzle I decided to dedicate it to the local school of Geiranger.
The puzzle becomes extremely simple as you understand the simple mechanics of the waterfalls (for that giving a look at the original puzzle might be furtherly helpful).