Logic Masters Deutschland e.V.

Rules:

Normal Sudoku rules apply: place the digits 1-9 in every row, column, and 3x3 region.

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

3x3 region borders divide the loop into segments. Every loop segment acts as a Nabner line: no two digits on a segment can be consecutive, regardless of their position on the segment. A 3x3 region can have multiple segments, and single-cell segments inherently satisfy this constraint.

Digits separated by a white dot are consecutive. Digits separated by a black dot have a ratio of 2:1. Not all possible dots are necessarily given.

For each given dot, at least one of the digits touching the dot must be on the loop.