**Rules of 9x9 Kropki Sudoku**

Classic Sudoku Rules apply. Additionally, if the absolute difference between two digits in neighbouring cells equals 1, then they are separated by a white dot. If the digit is half of the digit in the neighbouring cell, then they are separated by a black dot. The dot between 1 and 2 can be either white or black.

A Kropki Sudoku puzzle consists of a standard Sudoku grid with the addition of either black or white circular markers between neighbouring pairs of squares. Black circles show all adjacent pairs of squares where the value in one square is double the other, while white circles show all pairs where one value is consecutive to the other. 'Consecutive' means that the numbers in the two squares have a numerical difference of '1'. For example: 2 and 3 are consecutive, as are 6 and 5.