At my club, there is one player, who always touches the cork part of the shuttlecock with his racket frame before serving backhand... is this legal?
With your vague description, it's hard to tell. Are they doing a double motion? Does it seem like they are attempting to serve on the 1st motion, but then serve on the 2nd motion? But from what I am understanding, it seems like they are holding their racket up to the bird to set up, and then start a backward then forward motion in which they serve. If that is the case, it is totally legal.
your opp can only do 1 swing (one motion of backward and moving forward) if he moves his racket forward, touching the cork and going back again, then it is illegal if he touch the cork without moving (before swinging motion) then it is fine
Sorry for the vague description. But it is quite a deceiving action he does. Initially he brings the racket forward to the shuttlecock, makes contact with the top of the frame... and seems as if he flicks the serve from there... not too much swing action... I guess I need to take a closer look again
^^ what you're describing is exactly the same way that fu haifeng serves... take a look at some of his videos... he's practically *flinging* the shuttle over the net!
. After he has done it several times (his habit), I would expect you to know it the next time. Post #2, from CantSmashThis, explains it correctly. .