Normal Sudoku rules apply. Each (marked) diagonal has the digits 1-9 once each. Digits in cages sum to the small clue in the top left corner of the cage. Digits cannot repeat within a cage. The blue cells in box 9 sum to 10. The grey line forms a palindrome ie it should read the same backwards and forwards. The three cells with grey squares in them contain even digits. Clues outside the grid give the sum of the digits along the indicated diagonal. Digits can repeat along these diagonals.