in this lesson I'd like to talk, even though the topic is not among the easiest, about the II, V, I in the minor key, trying to give you some good indications and being as clear and easy as possible.
Obviously I can't explain the whole harmony in minor key in just a page, and so I'll take for granted that you already know the armonization of the harmonic minor scale, or at least its V and VII grade.
As you know, differently from the major mode where we have the IIm7 - V7 - I7+, in the minor mode we have the IIm7(5b) - V7(9b) – Im.
But this isn't all.
The fifth grade is the most interesting one, and it can be marked in different ways, and we''l talk about this, indicating also the scale and the fingering to use.
Let's start from the beginning.
First of all we'll use the key of C, the easiest to deal with, when makin' examples. The tonality of C major doesn't have accidents; on the other hand the minor one (relative of Eb major), has three "b" in the key: Bb, Eb, Ab. On the fifth grade we'll use the harmonic minor scale of C, starting from G. It will spell G, Ab, B, C, D, Eb, Ab, F, G. This scale is also called "Spanish Phrigia", and it has the minor second (ninth), major third, minor sixth, minor seventh. So it would be better spelled like this: G7(9b, 6b).
When using modal scales remember you should NEVER use the mysolidia scale over the fifth in the minor mode.
Many times the chord can be written as G7(9#, 5#), as in the popular standard "Blue Bossa".
In this case the superlocria scale is mostly used, also used over G7 9#.
What is the superlocria scale? It's found on the seventh grade of the melodic minor scale. Takin' G as the seventh grade of Ab, starting from G we have G, Ab, Bb, B, Db, Eb, F, G. We have obtained a scale by altering the second (Ab and A#) and the fifth (Db and D#), and leaving unaltered the fundamental (G), the third (B), the seventh (F). It's a scale formed by a part of diminished scale for the first four notes, and a part of esatonal scale for the following notes.
Unlike the superlocria scale, the diminished scale doesn't alter the fifth and it's mostly used over G7(9b). The diminished chord is found on the seventh grade of the harmonic minor scale (in the key of C) and it's spelled B, D, F, Ab (which are respectively the third, fifth, seventh and ninth flat of the G chord. This is why over G7(9b) we can use the diminished scale or the diminished chord.
The G diminished scale is used starting from a semitone (semitone, tone, and so on...).
There are two good ways to memorize this scale: the first is to think about a lydian dominant scale, with the second (ninth) altered; the second way thinkin' about a dominant with an augmented fourth (C#) and with the second (ninth) altered (Ab and A#). As you can observe the natural E (which is the major sixth, but it can also better considered the diminished seventh) is "outside" the key of Cm, so it's important to be aware of it, when playing.
Generally speaking, try to avoid usin' the major sixth over G7(9b), expecially when accompaning, and leave priority to the notes of the chord.
I'm aware that the topic is not of the easiest, but remember that the correct and conscious use of scales over chords is a necessary step for a jazz musician, avoiding mistakes and not wanted dissonances, and of top priority when accompaning moving out from the mere chord arpeggio.
I talked about these three scales because they are the most used over G7(9b), even though many musicians use other types of scales (esatonal, augmented). It depends on the kind of dissonant effect we want to obtain.
As a conclusion, I remind you that the numbers over the notes indicate the suggested fingering that I utilize, expecially to "see" the original chord. Below there is the tablature.
As always, I'm available for further explanations.
Have fun, and see you next time.