Normal sudoku rules apply. Both main diagonals are marked with a blue line. On either diagonal, no digit can repeat. Digits along an arrow sum up to the digit in that arrow's circle. If two digits are adjacent on a black line, then one digit is double the other. If two digits are adjacent on a magenta line those digits are consecutive. The grid is covered in fog; placing correct digits will clear the fog in that cell and may also clear fog in other cells. No guessing is necessary.