Example 5. The I-IV-V progression (minor key) Still in a bluesy context, the I–IV–V chord progression is now made minor using the m7 chords of Cm7-Fm7-Gm7. Again, full chord shapes can be ...

Harmonic minor keys are used when writing chords. There is another version of the minor key known as the melodic minor. This is used when writing a melody. Each key signature has two possible keys.