The ii–V–I progression ("two–five–one progression") (occasionally referred to as ii–V–I turnaround, and ii–V–I) 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". Jazz ii–V–I progressions are extremely common in jazz. They serve two primary functions, which are often intertwined: to temporarily imply passing tonalities and to lead strongly toward a goal (the "I" chord). One potential situation where ii–V–I progressions can be put to use is in blues, whose generic form has no such progressions. In the example below, a simple 12-bar F blues is shown followed by a similar one with some basic ii–V–I substitutions (in bold). | → | |} In bar 4, instead of the simple V–I root motion in the original blues, the ii chord of the B7 (Cm) is included so that the measure is even more directed toward the following downbeat with the B7. In bars 8–10, instead of leading back to the tonic with the standard V–IV–I (blues cadence), a series of applied ii–V–I progressions is used to first lead to Gm, which then itself is reinterpreted as a ii and used to lead back to F7 through its own V, which is C7. In the last bar (the "turnaround"), the same type of substitution is used as that in bar 4. In practice, musicians often extend the basic chords shown here, especially to 7ths, 9ths, and 13ths, as seen in this example: iim9 V913 Imaj9 In jazz, the ii is typically played as a minor 7th chord, and the I is typically played as a major 7th chord (though it