When I was 18 my teacher, Peter Snyder, asked me to take over his Los Angeles Parks and Recreation guitar class for kids aged 8-14. It was my first teaching experience, and I was excited. Peter had suggested that I use the Carcassi method book to teach the 20 kids, none of whom had any guitar experience. Before the daunting task of digging into the Carcassi, I showed the class proper hand positions and how to sit.
After my 10 minute explanation on these finer points of classical guitar technique, it was time to make individual corrections. I was trying my best to be upbeat with the kids, making little jokes here and there. I approached a little blond-haired girl who was sitting well, but her left hand position was in need of some adjustments. “Let’s get your thumb in the right position” I said. Looking behind the neck of her guitar, I added, “Okay, where is your thumb?” The little girl looked up at me with sad eyes and said, “I don’t have any thumbs.”
After the boulder settled in my stomach, I suggested that she put her palm behind the neck as a way of gaining leverage. After the class, I spoke with her mother and suggested that it would be extremely difficult for her daughter to play guitar without a thumb on either hand. The thumbs are indispensable, right?
The left thumb is perhaps the most overused digit on our left hand. I cringe when I see guitarists push on their thumb with all their might. When they detect a buzz they try to eliminate the annoyance by pushing into the back of the neck - harder, harder, and then still harder! Sometimes, a guitarist will have made such a habit of this that their thumb muscle has developed into what looks like a bull frog throat bulging out. I’ve also seen guitars with dents all over the back of the neck from a thumbnail digging into the wood.
Not that I’m one to talk. I vividly remember my college days when I would maintain a left hand death grip while practicing the Villa-Lobos Etude No. 1. No matter how hard I worked, I would get buzzes during the passage where the chords descend by half steps from the 10th position down to the first position. The epiphany came when I realized that all the extra pressure that I was applying did not make it to my 3rd finger - the guilty party of those awful buzzes. Realizing that this was not good, I dropped the etude knowing that I should start out on a new track. The adage “work smarter, not harder” was beginning to take shape.
So, let’s get on with the discussion. First of all, rethink the role of the thumb. Consider that the left-hand thumb’s primary task is to balance the fingers, more specifically, the 2nd and 3rd fingers. The thumb and these two fingers are the core, so to speak, of the left hand. One problem for many guitarists is that they orient their thumb too much behind the index finger which makes the other 3 fingers have to reach, with the 4th finger often barely able to get to its fret. Most guitarists have better finger extension with their index finger than any other. So, if the thumb is put behind the index finger, it is balancing the finger that needs the least help. A simple method to get a feel for the thumb’s proper location is to hold a pencil with the left fingers and thumb as if all four fingers are on a string. Observe where the thumb seems to have the best leverage. Usually, this is behind the 2nd finger, or in between the first and second fingers.
To figure the balancing point of the thumb in the context of a piece, simply place your fingers to the strings on a chord or passage with no pressure on the strings and with the thumb away from the back of the neck. Then, lightly touch the thumb to the back of the neck and you will naturally find the best position. Frequently, the thumb finds itself in the wrong spot due to excessive pressure, and as a result, little adjustments tend not to be made. Ideally, the left thumb should be moving constantly, always re-balancing the fingers.
One of the best etudes for working on left thumb technique is the Carcassi Etude No. 2, op. 60. My usual approach is to have students simultaneously pluck the four-notes of each chord without playing the arpeggios – what I call “block chords.” I’ll have them play through the etude with no left hand pressure, just a feather light touch on the strings and with the thumb barely touching the back of the neck. If the student has relaxed shoulders, arms and hands, the movement from chord to chord will begin to smooth out, and their thumb will naturally find good balancing points along the neck. With chords that utilize an open hand position (where the fingers are aligned one per fret), such as a common first-position C major chord, the thumb should typically be in a position that averages the stretches between the fingers.
Another of my favorite exercises is first position scales. With each open string I’ll have my student pause for a moment, both to relax their left hand and to reposition their left thumb. As the days go by, this re-balancing becomes automatic to the point that no extra time needs to be taken. I advocate maintaining the same curvature for the left hand fingers for every string while playing scale-like passagework. What this means is that the left thumb should adjust its vertical position with practically every string change.
A simple test to determine whether your left hand curvature is correct is to lightly touch all four fingers to the 6th string at the third position. Then, move all of your fingers to the first string while maintaining the same finger curvature. In order to have the same finger curvature, you will have to move your thumb roughly behind the first string as well. Essentially, for linear passagework like scales, the thumb should be on the same vertical alignment as the fingers. This is opposed to leaving the thumb in the middle of the neck, thereby revolving around the thumb as a pivot point. This approach entails having a different finger curvature for each string due to six different hand positions.
Were I now in a situation where a student who didn’t have thumbs wanted to learn how to play the guitar, I would explore a variety of approaches. With a guitar neck of appropriate thickness and width, I think it would be possible for someone to learn how to play popular or folk-style guitar to a reasonable degree.
The class went fine, by the way, as soon as I ditched the Carcassi.