Watch the Left Hand Parallel Position online guitar lesson by Andrew Leonard from Beginner Method for Classical Guitar
Now that we have discussed right hand classical guitar technique, it's time to introduce left hand classical guitar technique. You'll learn how to create the "C shape" by curling you fingers, using the pad of the thumb, as well as playing on your fingertips and at the "high edge of the fret." We'll also discuss the first finger of the left hand leaning back a little bit when properly positioned.
Once you have the fingers properly positioned, you can learn to move from the knuckles. This is an essential aspect of left hand classical guitar technique. When you keep the fingers parallel to neck, you're in (you guessed it) parallel position.
If you play another style of guitar, you may find it interesting to know that the neck of a classical guitar is wider than any other type of guitar. Perhaps this is why left hand classical guitar technique pays so much attention to where and how the thumb is placed.
Oops! At 3:18 I say "3rd string" when I meant 3rd finger on the first string. I hope that by watching what my finger is doing it will make sense. My apologies for any confusion.