What is a German Augmented Sixth?

A German augmented sixth chord (often called the German sixth or Ger+6) is a type of chromatic chord used in tonal harmony that contains an augmented sixth interval and typically resolves to the dominant chord. It is one of the three common augmented sixth chords used in classical harmony, alongside the Italian and French augmented sixth chords.

The German augmented sixth chord usually contains four notes: the lowered sixth scale degree (♭6), the tonic (1), the lowered third scale degree (♭3), and the raised fourth scale degree (#4). The interval between ♭6 and #4 forms the augmented sixth. These two notes resolve outward by step to the fifth scale degree (5), which is the root of the dominant chord.

For example, in the key of C major, a German augmented sixth chord would contain the notes A♭ (♭6), C (1), E♭ (♭3), and F♯ (#4). The A♭ and F♯ form the augmented sixth interval and resolve outward to G, leading to the dominant chord. Because the German sixth resembles a dominant seventh chord, composers often use careful voice leading to avoid parallel fifths when resolving it to the dominant.