Normal sudoku rules apply. The purple/blue lines are "equal sum lines". ie The sum of the digits on a line within a particular 3x3 box must be the same for all the boxes the line passes through. Different lines may have different sums. eg r9c1 + r9c2 + r9c3 = r9c4 + r8c4 + r7c4 = r6c4 + r5c4. Digits along each line are also a set of non-repeating consecutive numbers (which can appear in any order).