[tongzilla]

In addition to what tonzilla said. Even if you have a flat left wrist (defined by your impact fix alignments) and have beautiful clubhead control... You also control the action of the clubface and the compression upon it via the hinge action/left wrist motion through the impact interval . A flat left wrist means it is flat against the the vertical plane of the hinge action you are using for the particular shot in hand....

Here's an interesting point which is not in the book. So please look away for those who's only into pure Homer Kelly.

The Golfing Machine says that the Left Wrist controls the Clubface. But once you've mastered the idea of producing different Hinge Actions with your Left Wrist remaining Vertical to one of the three Basic Planes, a very convenient way to control the Clubface is through the Lag Pressure sensed by Pressure Point #3. 'What?' you may ask, 'I thought Pressure Point #3 was only for sensing Clubhead Lag Pressure'.

Let me explain. When you're hitting a straight shot, your Pressure Point #3 should be directly behind ("aft") the Clubhshaft supporting to load at Impact. A curved shot is produced by the divergence of the Clubface to the Clubhead Path. Simply put, to impart slice spin on the ball the Clubface needs to be open relative to the Clubhead's Path, and vice versa for hook spin. This means you should feel your Pressure Point #3 being more under the Sweetspot with a slice shot and more on top of the Sweetspot with a hook shot.