Logic Masters Deutschland e.V.

Normal Sudoku rules apply.

5's live in Dutch Flats
All 5's in the grid must strictly have EITHER; a '1' directly above it AND/OR a '9' directly below it. It may have both, but it doesn't need both.
Examples provided below on an empty grid.

Region Sum Line
For each line, digits on the line have an equal sum N within each box it passes through.
N can be different for each individual line.
Each instance that a line enters a box should be treated separately.
Therefore R3C2 must be the same digit as R4C3.

Play CTC

This will be a weekly series for as long as my brain allows:
Dutch Flat Mates 1: Classic
Dutch Flat Mates 2: Thermometers
Dutch Flat Mates 3: German Whispers
Dutch Flat Mates 4: Region Sum Lines
Dutch Flat Mates 5: Sandwich Sums (15 Nov)