[EdZ]

If you see Hinge Action -- the Rhythmic Roll of the #3 Power Accumulator from Impact to the end of the Follow-Through (Both Arms Straight position) -- as being automatically induced by the Physics of Rotation (Hitting or Swinging), then you see it as a Zone #2 (Power) Component.

If, on the other hand, you see Hinge Action as the veneer control applied by the Flat Left Wrist to individualize that Motion -- independent of the Motion itself -- into the three distinct applications of Clubface Control (Close Only, Layback Only and Simultaneous Close and Layback), then you see it as a Zone #3 (Purpose) Component.

One not-so-minor problem: If you see Hinge Action as being purely a function of the Physics of Rotation, then what do you do with Vertical Hinge Action (and its Clubface Layback Only)? It is neither the natural byproduct of Hitting (Muscularly-Powered Angled Hinging -- Simultaneous Clubface Close and Layback) or Swinging (Centrifugally-Powered Horizontal Hinging -- Clubface Closing Only). It is always, then, regardless of Lag Loading procedure, a "deliberate mechanical manipulation" (6-B-3-0). And that can only be Zone #3.

I suspect the debate will continue on this one, but suffice to say, per 2-S there is a valid argument for both zone 2 and/or zone 3 per Yoda above.

Sometimes it is helpful to remember that humans 'divide' and 'categorize' for perspective, yet often that very act of trying to organize and describe gets in the way of the 'whole picture'.