This morning I worked on the “stride” section of “You Are My Sunshine.” I started writing it as kind of a joke, thinking, “How dissonant can I make this and have it still sound like ‘You Are My Sunshine’?” But then it started to grow on me, and I made some changes, applying what I’ve been learning in my “After You’ve Gone” stride course. So now this section is deliciously rife with 6ths, 9ths, and diminished chords. Not the epitome of sophistication, but I’m excited to move beyond triads and dominant sevenths.
For some reason, I’ve struggled with the final measure or so of this section. With the left hand striding on F major, I descend chromatically from an F6 (3rd inversion) to a diminished chord—which diminished chord, I have no idea. Maybe an F diminished? On the keyboard, I’m playing B, D, F, and A♭. From there, the left hand switches to C7 and my right hand descends chromatically to a C9 (B♭ on the bottom), then plays what I think is a C with a flat 9, but which also looks like a diminished chord (B♭, D♭, E, G), and then descends chromatically to F6 (2nd inversion).
It’s when I get to the C9 business that things start to fall apart. I spent more time than I should deciding when to switch to the C7♭9, and that may be part of the problem—it’s just not solid yet because I hesitated so long over what I actually want to play. But I think another part of it is that I don’t know what the chords are called. You can see in the previous paragraph that I know what I’m playing—but is the first diminished chord an F diminished? Is the second one a B♭ diminished, or a C7♭9?
I feel like if I can name it, I can play it.
I’m going to have ChatGPT proofread this blog post since I’m otherwise incapable of publishing anything without at least one typo. Maybe it’ll have an answer to my question, and I’ll be able to stop the awkward pause at the end of this section. Here is my video on it. If you're interested in ChatGPT’s explanation, scroll right on down after the video.
ChatGPT's Answer to My Harmonic Puzzle
Here is ChatGPT's explanation. It makes me sound like I have way more music theory intelligence than I actually do!
Now, to your harmonic puzzle.
First diminished chord: B–D–F–A♭.
That is a fully diminished seventh chord built on B: B–D–F–A♭. So the cleanest name is B°7 (B diminished seventh). Because diminished sevenths are symmetrical (stacked minor thirds), it’s also enharmonically D°7, F°7, or A♭°7. But in your context—F major moving toward C7—B°7 makes strong functional sense. It acts as a leading-tone diminished chord to C (vii°7/V in F). That’s elegant, not random.
Second cluster: B♭–D♭–E–G.
Spell that enharmonically: B♭–D♭–E–G = B♭–D♭–F♭–G? No. Better approach: think in relation to C.
C7♭9 = C–E–G–B♭–D♭.
Your notes: E, G, B♭, D♭. That’s C7♭9 without the root.
And here’s the neat part: the upper structure of a dominant 7♭9 chord (3–5–♭7–♭9) is itself a fully diminished seventh chord. In this case, E–G–B♭–D♭ = E°7.
So what you’re seeing is not a random diminished chord. It’s the upper structure of C7♭9. Jazz harmony does this constantly: dominant 7♭9 chords and diminished sevenths are intertwined species.
So to summarize cleanly:
• B–D–F–A♭ = B°7, functioning as leading-tone to C (vii°7/V).
• B♭–D♭–E–G = C7♭9 (rootless), equivalently E°7.
You’re not flailing. You’re using textbook dominant preparation into V resolving to I in F. The ear hears tension increasing toward C and then release back to F6. The theory is behaving.
The deeper observation is this: naming helps not because the label has magic, but because it anchors function. Once you recognize “this is vii°7 of V” or “this is rootless C7♭9,” your hands stop guessing and start aiming.
Stride players historically leaned hard into this exact dominant–diminished overlap. The language you’re exploring isn’t decorative; it’s structural.
The awkward pause at the end of the section probably isn’t harmonic confusion. It’s likely rhythmic hesitation while your brain debates the spelling. Once the function is internalized, that hitch should evaporate.
Harmony is a taxonomy game. Once you know the species, the animal stops looking like a monster.
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