In Lesson 4 on stretching, Mircea goes into the nuances of thumb position. He explains how it's sometimes important to move the thumb "out and down" from its usual resting position behind the fretboard.

This could mean moving the thumb under the fretboard, or even off the fretboard entirely — both of which give you a much larger range of motion for demanding stretches.

You'll see how all the concepts you've learned so far apply in challenging passages from Ashley Lucero's Mariner's Tale and Brouwer's classic work Un Dia de Noviembre...and how simple elbow and wrist motions will help you pull off larger stretches with ease.