I do aback hand serve "raise the shuttle over the head, so when I drop the shuttle I directly smash through the net. Is that illegal?
From the laws of badminton: http://www.worldbadminton.com/rules/#9 Service: 9.1.5 the whole shuttle shall be below the server's waist at the instant of being hit by the server's racket. The waist shall be considered to be an imaginary line round the body, level with the lowest part of the server's bottom rib; 9.1.6 the shaft of the server's racket at the instant of hitting the shuttle shall be pointing in a downward direction; So, the answer is yes, it's illegal. Nice drawing, BTW.