Normal sudoku rules apply. Digits may not repeat in a cage and must sum to the number in the top left corner of the cage. Adjacent digits along a thicker orange line must differ by at least 4. The 3x3 box borders divide the thinner blue line into segments, each of which has the same sum. Digits in orange circles count the total number of odd digits along the line connected to the circle, including the circled cell. Digits on a thin green line with circles at both ends sum to a two-digit number; the 'tens' digit of this sum is in one circle and the 'units' digit is in the other circle.