Toolkit: dim to 7b9

A progression that comes up often is a diminished chord followed by a dominant 7b9 a fourth up.  It’s a form of ii-V, sometimes in an ending cadence or turnaround.

The easy way to get through it is to treat them as the same chord.  They’re the same notes, excepting the bass.  Technically, they imply different scales (though the pairing defines the scale of the 7b9), and it matters a good bit what comes before and after; but there’s nothing wrong with keeping it simple and playing with small arpeggios from time to time.

“Stella by Starlight” is full of these, as is “Dear Old Stockholm”.  My weakness here is a temptation to play the same lick each time they come around, essentially doing a turn of root, b9, root, 7 of the second chord.  Sometimes I’ll do an arpeggio of the diminished chord with a half-step trill on each note.  Chromatic slides along the diminished arpeggio work too.  (I’m using a fully diminished chord, four notes each a minor third apart.)

If I have enough of these gestures ready to hand, I can pick one that fits in whatever larger phrase I’m constructing.  This is a very fluid chord change, and I’ve been able to internalize it pretty well, so I’m fairly graceful with it.  (And therefore I like “Stella” and “Stockholm”.)  It helps that there are only three fully diminished chords (spelling can cause you to see a lot of different 7b9s).

Taking it farther, Mark Levine (The Jazz Theory Book) points out that Fmin-maj9, Gsusb9, Abmaj7#5, Bb7#11, Dm7b5, and E7Alt are in fact all the same chord–unless you’re the bass player!