The ii–V–I progression ("two–five–one", occasionally referred to as the ii–V–I turnaround) is a common cadential chord progression used in a wide variety of music genres, including jazz harmony. It is a succession of chords whose roots descend in fifths from the second degree (supertonic) to the fifth degree (dominant), and finally to the tonic. In a major key, the supertonic triad (ii) is minor, and in a minor key it is diminished. The dominant is, in its normal form, a major triad and commonly a dominant seventh chord. With the addition of chord alterations, substitutions, and extensions, limitless variations exist on this simple formula.
The ii–V–I progression is "a staple of virtually every type of [Western] popular music", including jazz, R&B, pop, rock, and country. Examples include "Honeysuckle Rose" (1928), which, "features several bars in which the harmony goes back and forth between the II and V chords before finally resolving on the I chord," "Satin Doll" (1953), and "If I Fell".
