Italian sixth
The simplest form of augmented sixth chord, containing only three notes: the flattened sixth, the tonic, and the raised fourth scale degree
In Depth
The Italian sixth (It+6) is built from the bass note (♭6̂) with a major third and an augmented sixth above it. In C minor, it would be A♭-C-F♯. The augmented sixth interval between A♭ and F♯ resolves outward by semitone to a doubled G (the dominant). Its spare, three-note texture gives it a leaner sound than the French or German variants. Despite its name, the chord was used throughout Europe.
The Italian sixth is the only augmented sixth chord without a perfect fifth or augmented fourth, giving it a uniquely hollow, open sound.