Scale Tone Chords
In any key it is possible to build chords on each degree of the scale. This means that for every major scale there are seven possible chords which can be used for creating keyboard parts and harmonising melodies. These seven chords are called scale tone chords. It is common practice to describe all the chords within a key with roman numerals as shown below in example 89 which demonstrates the seven scale tone triads in the key of C major.
Once you know the notes for any of these chords, there are three possible inversions for each one, which opens up many new possibilities for finding chord shapes which are close together on the keyboard. 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 move to other inversions. This progression would be described as 1 3 4 5 3 6 4 5. Try playing the same progression using different sets of inversions, e.g. beginning with a 2nd inversion C chord.
By using the correct formulas, it is possible to build any of the four types of triads on any note of the chromatic scale. E.g. if you start with the note D and add a note a major third above it (F#) and a minor third above that (A) you end up with a D major chord. If you start with the note A and add a note a minor third above it (C) and a major third above that (E) you end up with an A minor chord.
If you go through and analyse all of the scale tone chords in the key of C major you come up with the following pattern:
This pattern remains the same regardless of the key. This means that if you look at the scale tone triads in any major key, Chord 1 is always major, chord 2 is always minor, chord 3 is always minor, etc. The only thing that changes from one key to the next is the letter names of the chords. This can be demonstrated by looking at the scale tone triads for the key of G major which are shown below in example 91.
