Normal sudoku rules apply. Digits in a cage sum to the number given in its corner. Digits may not repeat within a cage. In any row or column, no more than two consecutive digits may have the same parity (i.e., be both odd or both even). Eg A sequence such as 2–4–5–7 is valid; but 2–4–6–3 is not valid, since three even digits appear consecutively.