Understanding the II-V-I

Two, five, one

The II-V-I, or "two-five-one", is a three-chord progression that closes a phrase. It is found in many genres and is extremely common in jazz: Honeysuckle Rose (1928) goes back and forth between the II and the V before landing on the I, and Satin Doll (1953) uses it too. In C, the standard jazz version gives each chord its seventh:

• Dm7 (D, F, A, C), the II. In a major key it is minor, so the map writes it in lower case, ii7.
• G7 (G, B, D, F), the V, the seventh chord that calls for the I.
• Cmaj7 (C, E, G, B), the I, with a major seventh: B, not the B-flat of C7.

The lesson runs it through a sixteen-bar A A B A form: the same II-V-I three times (Dm7, G7, then Cmaj7 for two bars), each time closed by a perfect cadence, the V settling on the I, and a bridge in bars 9 to 12.

Guide tones

To make a seventh chord heard, two notes are enough: its third and its seventh, the guide tones. In Dm7, G7 and Cmaj7, they are F–C, B–F and E–B. Turn the G7 pair over into F–B, and the three pairs connect almost without moving: at each chord change, one note stays, the other drops a half step.

• From Dm7 to G7: F stays; C, the seventh of Dm7, drops to B, the third of G7.
• From G7 to Cmaj7: B stays; F, the seventh of G7, drops to E, the third of Cmaj7.

Hence the rule the lesson puts into music: the seventh of one chord falls onto the third of the next. The right hand sings it: over Dm7, it climbs F, A, C, and its held C falls to the B of G7. The left hand keeps its F from Dm7 to G7, then drops it to the E of Cmaj7.

The bridge, in minor

In the bridge, the same progression moves into minor, heading for A minor. In a minor key, the II chord is diminished; in jazz it gets a seventh and becomes the m7♭5, the "half-diminished" chord. Hence Bm7♭5 (B, D, F, A), E7 (E, G-sharp, B, D) and Am, in bars 9 to 11.

The map, which reads everything from C, names them differently: viiø7 under Bm7♭5, because B is the seventh degree of C (ø marks half-diminished), and V7/vi under E7, "the V of vi", the chord that announces A minor, the sixth degree. Seen from A, it is still a II-V-I: the A the right hand holds over Bm7♭5 falls to the G-sharp of E7. Then bar 12 links Dm7 and G7, two beats each: a II-V that stops on the V (an imperfect cadence, says the map) and leads back to the last A, in C.

Throughout, the left hand plays the Charleston rhythm: a chord on the first beat, the same chord on the "and" of the second, held to the end of the bar.

How to approach it

My plan takes you through it in 8 days, so that the II-V-I stays in your ear and under your fingers.

1. Start with the left hand alone, in half notes, with its three notes, root, third and seventh: Dm7 (D, F, C), G7 (G, B, F), Cmaj7 (C, E, B). Chain them without looking; the F shared by the first two is your landmark. In the bridge, Am has no seventh, so it takes its fifth (A, C, E).
2. Then the Charleston rhythm. Count "1, 2 and, 3, 4" and play on "1" and on "and", as steady as a clock; only bar 12 switches to half notes.
3. The right hand alone, singing its held notes: the C of Dm7 falling to the B of G7 is the whole II-V-I in two notes. Then hands together: when the right hand climbs through a chord, its first eighth note falls alone, on 2, the second with the left hand, on "and".
4. The passages I point out are three downward leaps in the right hand, each after two beats of rest: bar 7, the fifth from B to E (as in bars 3 and 15); bar 9, the start of the bridge, from high E to D, more than an octave lower; bar 11, the sixth from G-sharp to C. Place your hand during the rest, eyes on the landing note.
5. Then transpose. In F, the same path gives Gm7, C7, Fmaj7: find its guide tones first.