Logic Masters Deutschland e.V.

Rules:
Normal Sudoku rules apply.

Draw a one-cell-wide loop of orthogonally connected cells. The loop may not touch itself, not even diagonally.

The loop acts as a German Whispers line (i.e., adjacent digits on the loop must have a difference of at least 5).

Digits in circles count the total number of loop cells that are a chess knight's move away from the circled digit. The circled digit may be either on or off the loop. Not all possible circles are necessarily given.