10-18-A Standard Wrist Action & 10-18-C Single Wrist Action

[Yoda]

It's not possible for the left wrist to turn and roll and not the right,
unless you do something 'funny' with the right hand grip.

In an ideal world, MJ is right. Unfortunately, one man's 'funny' is another
man's 'habit.' And misaligned 'habit' executing its ignorance sabotages
performance.


Many otherwise correct Top positions are ruined by insufficient Right Wrist
Turn. Often, this condition can be traced to a perverted 'Position Golf'
attempt to maintain the Elbows 'close together' -- by actively pulling the
Right Elbow 'in' toward the Left -- throughout the Stroke. The cure is to
establish and maintain the correct Left Arm and Right Forearm (and Elbow)
Flying Wedge Alignments (6-B-3-0-1 and 12-3-0 #23).

[Yoda]

Yoda,

The left wrist "Turn" is a clockwise rotation of the left
forearm from the elbow down and changes the orientation of the hand and
forearm to the upper arm. This doesn't happen in Single Wrist Action unless
actively and intentionally done by the player, and at that time becomes
Standard Wrist Action.


[Bold by Yoda.]

We are in complete agreement. The key word is Rotation. With Standard
Wrist Action, the player actively Turns -- Rotates -- the Left Wrist On Plane
during Start Up. With Single Wrist Action, the Left Wrist gradually Turns
(with the Turning Body and Orbiting Arm) throughout the Backstroke and
reaches the Top in its Fully Turned (On Plane) condition. At no time is there
an independent Wrist Rotation by the player.