Where did you get the Snead photo? Is there an entire sequence?
I'll answer for Mathew.
Annikan provided the photo at my request to begin a thread earlier this year. If he has the entire sequence, I'm sure he would be happy to post it.
The point was to make obvious the true direction of the spine tilt in the Start-Up and Backstroke, i.e., the bottom moves slightly away from the Target with the Weight Shift (a Hip Motion) as the Head remains steady. It is the Standard Pivot (10-12-A) and Standard Hip Turn (free Turn and Weight Shift / 10-14-A) illustrated in Photo 9-1-5 of The Golfing Machine. It is not a Reverse Pivot.
In contrast, some instructors -- perhaps even most -- teach that the top of the spine tilts away from the Target in the Backstroke. They label the move as an "athletic" Pivot. I label it a Sway.
Look again this rear-view photo of Sam Snead and draw your own conclusion.
This is good information, and the picture(from Annikan) sheds a different light on the SPINE, HIPS, KNEES, and HEAD during this part of the PIVOT.
Have you come up with a ZONE 1 PIVOT DRILL or EXERCISE to help people see how this works, or is CHAPTER 9 IT(a pivot drill)?
My appeal is to common sense.
Standing erect without a club and while keeping your head still, shift your weight to your right foot. Do not turn...simply allow your weight to go to your right side.
Which part of your spine moved with the hips? The top?