Normal sudoku rules apply. Clues outside the grid give the sum of the digits along the indicated diagonal. Digits separated by a white dot have a difference of one, while digits separated by a black dot are in a 1 to 2 ratio (ie one digit will be double the other). Not all possible dots are given. Cells separated by a single knight's move (in chess) do not contain the same digit. Cells separated by a single king's move (in chess) do not contain the same digit.