If one wants to understand supination, radial/ulnar deviation, flexion, and how the clubface is controlled by the hands/wrists refer to Homer Kelley's book "The Golfing Machine". <---Mac O'Grady and Gary McCord go nuts on TGM. 99% of hacks have no interest nor any idea what this is about nor do they care. BUT, all pros do these factors some of them somewhat differently, but ALL do them very well. In fact, I'll go out on a limb and say 80%+ on this forum have never felt what Marty Nowicki shows in the use of Kelvin Miyahira's invention the Impact Snap. The Impact Snap puts your hands, wrists, arms in these positions which like I say most have never felt. BTW, there is no right or wrong if you don't like this stuff just pass over it. This is for folks that want to understand more. The OP asked a question so here's more info. that many have not even considered.