I was recently asked about how to play the second chord in Jobim’s Wave. I don’t think my correspondent would mind me saying that he’d got himself rather tangled up in analysis and choices of diminished chords.
Here’s where the most helpful thing I’ve ever encountered comes in – it’s called the “huh?” chord. You sometimes analyse tunes ahead of time, and often while you’re actually playing them.
The first bit of Wave goes:
DM7 Bbo Am7 D7b9
So we’ve got:
I Huh? IIofIV VofIV
Everything else is pretty natural and obvious except the “huh?” bit. So what could we put in there? Looking at the melody, I’d be naturally tempted to try a V chord. Let’s do that and give things a bit of a twist to suit the melody and we get this:
DM7 A7b9 Am7 D7b9
This works nicely, but there’s boring root motion between bars two and three, right? So to give it more activity, we can do this:
DM7 A7b9/Bb Am7 D7b9
And A7b9/Bb is Bbo. So that chord is a V7b9 disguised by its alternative root – or at least, we can think of it in that way. And the scale would be A half-whole diminished (or Bb whole-half). Which perfectly fits the melody line at that point – F# G Bb Db E G F# A.
Of course there are other things you could do, but that seems to me to be the intent behind the tune – and nothing matters more. Or at least you might say that it’s important to understand the intent, then you can choose to alter things if you wish.
Bossa writers seem to have had a thing about notating with diminished chords (and not all examples work quite like this) – it might be to do with them mostly being guitarists.
The takeaway is that when you find a bit in a tune that you don’t understand, call it “huh?” and move on to get the whole structure around it. Once you have all that clear, come back and you’ll find it much easier to find a solution to the “huh?” bit.
And if you’re figuring out the tune while playing it, keep things simple at that point until you’ve had a chance to figure things out or (quietly) try out a few options as you go.
When analysing harmony – whether it’s a jazz tune or a symphony – look at the walls first, then worry about the windows.
PS There’s more to this specific example – but it’s quite high level stuff. Just as we can think of “secondary dominants”, there are also “secondary diminished chords”. Worth a Google, if you’re curious and don’t mind a bit of an extra headful.