Logic Masters Deutschland e.V.

Triplex by Nicolas Duhail.

Rules
Normal sudoku rules apply.
This puzzle is solved in 3 stages.
First stage: solve the puzzle using "lockout lines" rule. After completion, erase all digits except those in blue cells.
Second stage: solve the puzzle using "double arrows" rule. After completion, erase all digits except those in yellow cells.
Third stage: solve the puzzle using "between lines" rule.
Lockout lines: Endpoints must differ by at least 4. Digits on the line must fall strictly outside the endpoints.
Double arrows: The sum of the digits along the line is equal to the sum of the digits in the circles at each end of the line.
Between lines: Digits along the line must be between the digits on the circled ends of the line.