Several guys in my club say that my service is a violation. In double backhand service, my left wrist (non shooting hand) has a slight upward flip and then right hand racquet hits the base of the birdie almost at the same time. They are not complaining over waist, over hand, not hitting base, delay or anything else, they say that my left hand can not flip the bird upward, I can only release it. In that sense, I cannot throw the bird up to the air, wait until it's low enough and hit it either. Mine stroke is a mini version of that, although I hit the bird when it's going upward. So I check the rules tonight, it doesn't even mention the non-shooting hand, am I not getting the complete rule, or their interpretion is wrong? Thanks for any comment. The service rule I found is listed below. 11. SERVICE 11.1 In a correct service: 11.1.1 Neither side shall cause undue delay to the delivery of the serve. 11.1.2 The server and receiver shall stand within diagonally opposite service courts without touching the boundary lines of these service courts; some part of both feet of the server and receiver must remain in contact with the surface of the court in a stationary position until the service is delivered (Law 11.4); 11.1.3 The server's racket shall initially hit the base of the shuttle while the whole of the shuttle is below the server's waist; 11.1.4 The shaft of the server's racket at the instant of hitting the shuttle shall be pointing in a downward direction to such an extent that the whole of the head of the racket is discernible below the whole of the server's hand holding the racket; 11.1.5 The movement of the server's racket must continue forwards after the start of the service (Law 11.2) until the service is delivered; and 11.1.6 The flight of the shuttle shall be upwards from the server's racket to pass over the net, so that, if not intercepted, it falls in the receiver's service court. 11.2 Once the players have taken their positions, the first forward movement of the server's racket is the start of the service. 11.3 The server shall not serve before the receiver is ready, but the receiver shall be considered to have been ready if a return of service is attempted. 11.4 The service is delivered when, once started (Law 11.2), the shuttle is hit by the server's racket or the shuttle lands on the floor. 11.5 In doubles, the partners may take up any positions which do not unsight the opposing server or receiver.