Other Useful Chords
The Diminished Seventh
Diminished chords are easy to form: simply build up three minor thirds (one and
a half tones) on top of any note to form its diminished seventh. There are really
only three distinct diminshed chords, because all others share the same notes.
The upper staff shows the components of the C diminished seventh. Below is a
useful movable diminished form. The D diminished contains the same notes as the
Sixths, Ninths, and Major and Minor Sevenths
Other commonly used chords are the sixth, ninth, and major and minor seventh,
formed as follows:
For the sixth, add the sixth note of the scale to the tonic (one) chord.
The ninth is formed by adding the ninth note to the dominant seventh.
In this case, the C9 in root position is impractical on the guitar. Dropping
the fifth (G) is acceptable, and results in a useful movable shape.
The minor seventh is formed by adding a seventh note to the minor chord.
As before, the chord at (b) is more practical for the guitar, also the useful
movable shape in the chord block.
The major seventh is formed by raising the seventh note of the dominant seventh
by a half step:
A glance at the sheet music of contemporary songs will show many chords altered
from the common forms, particularly songs with a modern jazz flavor. Some sheet
music gives chord blocks, but the quality of chords suggested is sometimes dubious.
A better plan for enlarging your chord repertoire is to work through a classic
such as the one by George M. Smith, a former top Hollywood studio musician, which
is still considered one of the best available.