Welcome to LivingPianos.com! I’m Robert Estrin. Today, we’re diving into the most deceptive chord in music: the augmented sixth chord. Now, if you’re like many people, you might have heard of it but don’t really know why it’s so special or, frankly, so tricky. So, let’s break it down in a way that makes it easy to understand and maybe even a bit fun!
What Exactly is an Augmented Sixth Chord?
At its core, the augmented sixth chord sounds like a dominant seventh chord. But here’s the twist—it’s not built on the fifth scale degree (like a normal dominant seventh). Instead, it’s built on the flatted sixth scale degree. Confused yet? No worries; we’re going to go step-by-step to clear it up.
Building the Augmented Sixth
Let’s start with a basic major scale:
• In C major, the notes are: C, D, E, F, G, A, B, and C.
• The sixth note of the scale is A, but for the augmented sixth chord, we lower it a half-step to A-flat.
Now, you start building the chord in the typical way stacking thirds, A-flat, C, E-flat. But for the top note, instead of the 7th, G-flat, you add the augmented sixth. So, you end up with this: A-flat, C, E-flat, F-sharp!
That interval between A-flat and F-sharp is what makes this chord augmented—it’s the same note on the piano as the 7th of a dominant chord, G-flat, but it’s written as an augmented sixth, F-sharp, so it resolves differently, which really has an unexpected sound.
The Resolution: Where It Gets Sneaky
Normally, you would expect a dominant seventh chord to resolve to the tonic (a V-I progression). But when you play an augmented sixth chord, it deceptively resolves to a key you didn’t see coming! For example, let’s go back to that C major scale. When you play the augmented sixth chord (A-flat, C, E-flat, F-sharp), it doesn’t resolve to a D-flat chord like you would expect since A-flat is the V of D-flat. (Dominant 7th chords are V7 chords that resolve to I.) Instead, it resolves outward to an entirely different key, C major or minor!. It’s this surprise resolution that gives the augmented sixth its sneaky, deceptive character.
Three Varieties of the Augmented Sixth Chord
Now, here’s the fun part—there are actually three different varieties of the augmented sixth chord, each with its own little twist. Let’s take a look at them:
1. The German Sixth
The German sixth is the most commonly heard form of the augmented sixth chord. It’s made up of the following notes: A-flat, C, E-flat, F-sharp. It has that dominant seventh sound, but again, instead of resolving to the tonic, it resolves outward, usually to C major or minor chord with G on the bottom, the second inversion of the tonic chord. It has a fresh, unexpected sound!
2. The French Sixth
The French sixth is similar to the German sixth but with a slight twist. Instead of using the perfect fifth interval (as in the German sixth), it replaces it with an augmented fourth. This creates a different flavor, almost like a little bit of spice added to the chord. So instead of A-flat, C, E-flat, F-sharp, it’s A-flat, C, D, F-sharp.
This chord can resolve to either the C major chord with G on the bottom, or to a G dominant 7th chord, G, B, D, F.
3. The Italian Sixth
The Italian sixth is a simpler version, where you omit the fifth note of the chord (E-flat) and you double the third, C. This is done to provide better resolution. So this chord can also resolve to C major or minor chord in second inversion (with the G on the bottom), but also can resolve to a G dominant 7th, G, B, D, F. It still gives you that dominant seventh sound, but without the problematic parallel fifths which composers avoid in music.
The augmented sixth chord is so interesting because it’s not just a chord—it’s a way of tricking your ear. You expect it to resolve in one direction, but it surprises you by resolving somewhere else. This chord has been used in classical and modern music to create tension, surprise, and harmonic color. Once you understand how it works, you’ll start hearing it in all kinds of music, from Bach to Chopin, and even in film scores. It’s one of those “ah-ha” moments in music theory!
Wrapping It UpTo recap, the augmented sixth chord is a deceptive chord that sounds like a dominant seventh chord but is built on the flatted sixth scale degree of a scale. It has three main varieties—German, French, and Italian—each with their own distinct flavor and resolution. They’re a great tool for composers to add some unexpected drama to a piece, and now you’ll know exactly why they sound so unique!
For another deceptive chord, check these out:
WHAT IS A DIMINISHED 7TH CHORD? – PART 1
DIMINISHED 7TH CHORD – PART 2 – THE DECEPTIVE DIMINISHED 7TH
Let me know if you have any questions or want to explore more about how these chords pop up in actual music examples—I’m always happy to help!
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