Left Hand Position

I have been asked many times while teaching guitar. "where is the best spot for my thumb to be on the back of the neck". Here is what I tell my students.

Place your thumb on the midpoint of the guitars neck.

The thumb can move above the midpoint but should never move below it. In doing so would put your hand in an awkward position causing it to be harder to use your other fingers correctly

Don't allow your thumb to get too high up the neck. It should always be opposite of your other fingers.