Kropki Sudoku is a variant where white dots between cells indicate that the numbers differ by 1, and black dots indicate that one number is twice the other. All possible dots are given, meaning if there's no dot between two cells, then they do not satisfy either condition. Each row, column, and 3x3 box must contain the digits from 1 to 9 exactly once.
Pro? Record a master class and get V.I.P.