[metallion]

Tentative conclusion (Swinging) - based on 2-K and 2-M-4 in more or less pure English:

Rotation is what the (turning) body performs in order to accelerate and blast the essentially straight left arm into orbit and toward impact.

Good enough?

No.

Since the right arm is part of the power package (Lever Assembly) the right shoulder (2-H) has the responsibility to:
- line up the power package correctly by titing the axis around which the body rotates
and
- defining the degree of right elbow bend at impact and may thus influence the impact alignment of the clubface.

So ROTATION means:
- Rotating the body for centrifugal force.
- Rotating the right shoulder down on plane for alignments

Good enough?