Basics of the A Form on the Guitar
On the guitar, the A form is one of the most commonly used shapes and is typically what comes to mind when guitarists think of barre chords. You move up an open A chord and use it as an A form barre chord to play major chords all along the 5th string.
With this shape, the root is under your 1st finger on the 5th string. Here are four examples to get you started.
The most popular fingering for this shape includes barring with your 3rd finger to play strings 2 through 4, but you can also use separate fingers if you prefer. If you barre with your 3rd finger, you may find it necessary to leave out the note on the 1st string because it’s difficult not to bump into it.
This in turn means that you don’t need to barre with your 1st finger because it’s only fretting the root on the 5th string. If you should need the note on the 1st string to ring clearly, then skip the barre and use separate fingers to fret each note individually.
Some people can barre with their 3rd finger and still get the note on the 1st string to ring clearly. Experiment to see which fingering technique works best for you.
After you play the A form barre chord, play the A form arpeggio pattern as shown in the four examples here. Remember that you play these notes individually from lowest pitch to highest pitch in an ascending order like a scale; then reverse direction.
Use the diagrams to play major arpeggios for roots along the 5th string. Numbers are used to show the intervals in the first three diagrams. The fourth example includes a sample fingering.
The A form arpeggio pattern has two additional notes that aren’t part of the barre chord. This includes a note on the 6th string and another on the 4th string. Notice that you play two notes in all on the 4th string.
You can break up this arpeggio into various chord voicings. Remember to fret and play only the black dots. The clear dots are only to show where the remainder of the whole form is. Try the suggested fingerings here or use your own.
A uses only strings 1 through 3. Led Zeppelin uses this shape in the interlude to Stairway to Heaven as both a type of C, as shown here, and a type of D two frets higher.
B features a shape on strings 2 to 4 that’s often used together with a C form on the same strings. You can barre these three notes with your 1st finger to play a C and then add your 2nd and 3rd fingers to play an F in C form, as you hear in Brown Sugar by The Rolling Stones.
C shows a standard power chord shape that’s used on countless songs.
D shows one way to incorporate the extra arpeggio note on the 4th string. John Mayer uses this shape in the chorus of Daughters.
E is similar to Figure 4-11d, minus the root D on the 5th string. This D/Fs, which is really only a root and 3rd, shows up in the chorus to All Right Now by Free.
F uses the extra arpeggio note on the 6th string. It’s an F power chord with the 5th, C, in the bass and is used in the opening to The Wind Cries Mary by Jimi Hendrix.
G is an F played as only a root and 3rd and is used in Scar Tissue by Red Hot Chili Peppers. This interval is often called a 10th because the 3rd is a register above the root, ten steps in the major scale.
H is a C and is arpeggiated in the opening to Cliffs of Dover by Eric Johnson.
If only the root and 5th are used in a chord, it’s considered a power chord, and you write it as C5, F5, and so on. If only a root and 3rd are used, then you sometimes see it written as G(no5).
However, most of the time a root and 3rd combo is still considered a major chord and is written as such, even though the absence of the 5th technically makes it incomplete.
Guitarists often combine the two sets of chord voicings by barring the A form on strings 2 to 4 with the 1st finger and then adding the 2nd and 3rd fingers to build a partial C form, as is the case in Jack and Diane, Funk #49, All Right Now, and many others. Keith Richards uses the same technique in most songs by The Rolling Stones.