Normal sudoku rules apply. Cells in the same relative position with respect to a box cannot contain identical digits. (So eg, r1c1 and r4c4 cannot contain the same digit). Clues outside the grid give the sum of the digits along the indicated diagonal. Digits along such a diagonal may repeat if allowed by other rules. The digits along lines in the grid must be BETWEEN the two digits in that line’s circles (eg if the circles contained 2&7 then the digits on the line could only be from 3/4/5/6). Digits on the lines may repeat if allowed by other rules.