Normal sudoku rules apply. The grid is covered in fog. Correctly placing a digit will clear any fog in its own cell, and potentially clear fog in other cells too. Each row, column, and 3x3 region contains exactly one given digit whose exact location is to be deduced. No two givens are identical digits, i.e. each of the digits 1 to 9 is given exactly once. A clue outside a row or column indicates the sum of all digits up to the given digit (the given digit itself is not included in the sum). Digits on an arrow sum to the digit in the circle from which the arrow emerges. Digits joined by a black dot have a 1:2 ratio. Digits joined by a white dot are consecutive.