In any key it is possible to build chords on each note of a scale. This means that for every major scale there are seven possible chords which can be used for creating guitar parts and harmonizing melodies. These seven chords are called scale tone chords. It is common practice to describe all the chords within a key with roman numerals. The following diagram demonstrates the seven scale tone triads (three note chords) in the key of C major.
Here are the seven scale tone triads in the key of C played as arpeggios.
The ascending pattern in bars 1 to 4 begins on the root of each new chord, while the descending pattern in bars 5 to 8 begins on the 5th of each new chord. Use alternate picking and make sure all the notes are clear and even in both tone and volume.
Once you know the notes for any of these chords, you can use any fingering you like to play them. This may involve re-arranging the order of the notes or doubling some of the notes, but as long as the chord shape you are playing contains only the three note names involved in that particular chord, you are still playing the right chord. The following example demonstrates a common progression in the key of C. By analyzing the progression in terms of chord numbers, it is easy to transpose to other keys or use other fingerings. This progression would be described as I III IV V III VI II V. The chord shapes used in the next exercise are shown here.
C
Dm
Em
F
G
Am
Here is the same progression played fingerstyle as arpeggios. As you can see, there are many ways of playing any chord progression.