[EdZ]

It is important not to confuse the commonly used expression "wrist hinge" and what TGM calls "hinge action"

Innercity - a vertical hinge is different than cocking the left wrist. A vertical hinge has to do with how the clubface and ball meet (see chapter 2). It sounds like you are thinking of left wrist cock - a vertical motion - a seperate identity from a vertical hinge 'action'.

The left wrist cocks and uncocks (vertical motion).
The right wrist bends and arches (horizontal motion).

When the ball and clubface meet, the clubface can either close only (horizontal hinge action), close and layback (angled hinge action) or layback only (vertical hinge action).