Logic Masters Deutschland e.V.

Rules:

Each row, column, and 9-cell region in the grid must contain the digits 1 to 9 exactly once.

The regions in this puzzle must be determined by the solver. Each region is a 1-cell wide snake that cannot branch or touch itself orthogonally. Different regions may not share cells with each other.

A black dot between two cells indicates that the digits in those cells have a 2:1 ratio. These two cells must be in different regions.

A white dot between two cells indicates that the digits in those cells are consecutive. These two cells must be in the same region.

Not all possible white and black dots are necessarily given.

I recommend using the following link to play this puzzle on Penpa+. Answer check can be triggered by filling in all digits and completely surrounding each region using the green edge tool.

Penpa+