Logic Masters Deutschland e.V.

Note: This is a less common variant, which some call 'double arrows'. I've been calling it 'sum lines' and the rules are simple, as you'll see.

If you haven't tried this constraint before (or even if you have, and enjoy it!), I recommend trying my puzzle Shattered Glass first, as it is an easier introduction to the constraint.

If you enjoyed this, and you're looking for a much harder challenge, why not try Doppelt by tallcat?

Also, I have to say a HUGE thank you to NXTMaster for their tireless efforts in testing this puzzle - it was not an easy road, due to my inability to do basic arithmetic!

Rules:

Normal sudoku rules apply.

Sum Lines: The digits in the squares on the ends of a line must sum to the same total as the rest of the digits on that line.

Cells separated by a black dot must have a ratio of 2:1. Not all dots are necessarily given (no negative constraint).

F-puzzles link

SudokuLab link

CtC Web App link (has solution check)