Logic Masters Deutschland e.V.

Rules:

Normal Sudoku rules apply.

Digits along an arrow must sum to the digit in that arrow's bulb.

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

-- All arrow bulbs must be on the loop.

-- The digit in an arrow bulb gives the number of loop cells that bulb sees in all horizontal/vertical directions combined, including itself. Non-loop cells block the vision.

-- The loop acts as an entropic line. Each set of three adjacent digits along the loop must be one low [123], one medium [456], and one high digit [789].