Normal sudoku rules apply. Digits may not repeat along the marked diagonal. Cells that share the same relative position in 3x3 boxes may not contain the same digit (eg if there is a 1 in the top left cell of Box 1 there may not be a 1 in the top left cell of any other 3x3 box.) Digits in cages sum to the small clue in the top-left corner of the cage.