Logic Masters Deutschland e.V.

Apply classic Kropki rules (see below) with the following exception: White circles can be blackened. It is part of the puzzle to find out which circles have to be blackened.

Kropki: Place the digits 1 to 9 exactly once into each row and column. If there is a black circle between two cells, one of the digits must be twice the value of the other digit. If there is a white circle between two cells, the two digits have to differ by one. If there is no circle between two cells, none of the two properties may be true.