Revert,
Glad to hear you are getting the book. I referenced a few of the sections that relate to left wrist breakdown for others that want all the nitty gritty.
I'll give you the Bagger version and hopefully Yoda will step in and correct any of my misleading assumptions.
There are three things that cause clubhead throwaway in 6-D.
1.) The urge to throw the clubhead from the top with the wrist(s)
2.) Over acceleration
3.) The feel that you must uncock the wrist(s) to align the clubface for impact.
There are four "Snares" (3-F) that we must avoid:
1.) Steering is trying to keep the clubface square to the target line, or clubhead on the target line, or the Clubhead on a level or upward path through impact. This is due to emphasizing the flight line over the plane line.
2.) Quitting (substituting clubhead control for clubface control). This forfeits the swingers sequenced release of uncocking on plane, then rolling the left wrist into impact.
3.) Bobbing - raising or lowering the head during the swing
4.) Swaying - Incorrect weight shift.
Rhythm is the steady, consistent RPM of the left arm and clubshaft as the clubhead begins to accelerate at the release point and the clubface rotates into and through impact (2-G). The clubshaft is seeking it's inline relationship with the left arm as the left wrist uncocks and the left hand rotates. This causes the clubhead to accelerate geometrically and it requires a flat left wrist for the clubface to align properly (6-B-3-0) .
On the downswing, the left arm and clubshaft are in-line even though there is wristcock. We call this the "left arm flying wedge" (6-B-3-0-1). This basic in-line relationship alignment doesn't change as the left wrist uncocks, however the clubhead picks up speed as the clubshaft seeks a straight, inline relationship to the left arm.
The left wrist roll into impact is called "Hinge Action" and is clubface control. It's an imperative in The Golfing Machine that the left wrist stays flat during the release and followthrough sequence in order for the uncocking and hinge action to be geometrically correct. This is the only way to impart maximum compression into the ball and straightaway ball flight.
All of the above requires that the clubshaft, clubhead, and clubface are coming down, out, and forward on a straight plane line, and RPM is constant. Acceleration is handled by the release sequence and the golfers ability to sustain RPM as the clubhead begins it's acceleration, (overtaking) phase.
Whew...
No wonder we like to reference chapters in the book...
Bagger