[Bagger Lance]

Bagger, i found this point confusing. How do you aim at something underneath the ground?

I think of two lines on the surface of the ground. The primary line is the target line or base of the plane line. We all visualize this line from putt to drive.

The second line is the low point line and it's approximately half an inch outside of the target line.

The 4 sides of a plane extend to infinity in all directions. When we first make contact with the ball, we are contacting it "up plane" at separation the clubhead has moved "down plane" towards low point, below the ground. This is why we emphasis an inside/out impact.

If the ground were water and the plane was a flat sheet of metal, the base of the plane is where it intersects the surface of the water. If there was a horizontal line drawn on the plane half an inch below the water, you would see it just outside the surface line.

To see the low point plane line you need a visual reference on the surface of the ground. That reference line is within an inch of the plane baseline and just outside of it.

If you have the book, Homer made some drawings depicting these plane lines.
Hope that helps.