The ol’ one finger per fret rule is well and good for a while but soon enough you will find yourself stretching out for that extra fret. An extension is simply when a left hand finger reaches further than one fret from the adjacent finger. So, to give an example, if you had your first finger playing the fifth fret on the first string (A) and you extended your second finger to play the seventh fret (B) that would be an extension.
Another example. You are playing the eighth fret on the first string (C#) and you extend your fourth finger to play the twelfth fret on the same string (E) that is an extension.
So where would extensions be useful in playing?
I’m glad you asked.
Extensions are useful when you don’t have enough notes in a different part of the fingerboard that warrant a full shift. A shift can often break the legato line of music and it can involve string squeak and or a destabilization of the hand. By analogy it is like the choice of getting up out of your chair to reach the TV remote, or just stretching that little further with your arm to pick it up.
Another reason you might use extensions has to do with the distance between the frets. Spanning seven frets is quite difficult when you are down in the lower positions (near the first fret) however, if you are playing up around the twelfth position it is quite easier and it might be easier to use extensions to play passages as the fingers don’t get squashed together.
When I was first studying the Concierto de Aranjuez I found that all of the high passage work became easier by using extensions. The fingers aren’t cramped and you can also favour your second and third finger instead of the weaker fourth finger.
The three note per string scale is a great tool to practice extensions. Make sure your positioning of left hand fingers is correct and start in the higher positions if you find the stretch difficult to begin with. Have a go at the scales below:
C Major 2 octave using extensions
F Major 2 octave using extensions
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