Logic Masters Deutschland e.V.

Rules:

Normal sudoku rules apply: Place each of the digits 1-9 once in every row, column and indicated 3x3 box.

Behind the windows in this grid is a single loop. The loop has no dead ends and does not branch, cross itself or visit any cell more than once, though it may move diagonally.

Windows can be open, partially open or closed.

Open windows (such as r1c1) reveal every part of the loop which is behind that window.

Partially open windows (such as r1c9) reveal every part of the loop behind the window which travels downwards or diagonally downwards from the window's centre.

Closed windows (such as r3c3) reveal nothing about the loop.

There is fog in front of many of the windows, which can be cleared by placing the correct digit in the window's cell, or sometimes a nearby window's cell. No guessing is required to clear the fog.

Adjacent digits along the loop must differ by at least 5.