Normal sudoku rules apply. Along each positive diagonal (ie from SW to NE): 1) all the digits are different; and 2) adjacent digits (ie those touching at a corner) must have a difference of at least 4.
Normal sudoku rules apply. Along each positive diagonal (ie from SW to NE): 1) all the digits are different; and 2) adjacent digits (ie those touching at a corner) must have a difference of at least 4.