Understanding Rory's swing | Golf Monthly

Good slow motion clip

I think he is either closing the face on the immediate takeaway, or maintaining it square -0 he doesnt rotate his forearm, as is common.
also note he does not lift his left heel on the backswing, which surprised me, because for someone with a renowned hip turn on the downswing, i though he would have got that from teh stepping action from one foot to the other.

His full wrist cock seems to come only right at the end of the backswing, allowing him to really load the shaft.

His club line at teh top of backswing is below his initial shoulder-ball plane,

And finally, his right arm is not yet straight at impact, which i find particualrly interesting, but then i'm funny like that !