Most of us are familiar with the concept of relative minors, and how they relate to 6th chords. The 6th chords contain the same notes as the m7 chords, but the bass player uses a different note as the root.
C6 = Am7
D6 = Bm7
F6 = Dm7
G6 = Em7
A6 = F#m7
For many years I've struggled to find m7b5 chords (a.k.a. half
diminished) from jazz charts on my guitar. Recently I came to a
startling revelation - they contain the same notes as m6 chords, in the
same relationship as the relative minor. Check it out:
Cm6 = Am7b5
Dm6 = Bm7b5
Fm6 = Dm7b5
Gm6 = Em7b5
Am6 = F#m7b5
The m7b5 is the relative minor of a minor chord. Sort of. Anyway, it helps me find them on the neck, and that's what counts.