The ii–V–I and guide tones – free course

If the blues is jazz's mother tongue, the ii–V–I is its grammar. In countless standards, the harmony moves in little chains of three chords: Dm7 – G7 – Cmaj7 in C major. Being able to navigate this progression means being able to improvise over a huge part of the repertoire.

The three chords

Degree	Chord	Notes	Role
ii	Dm7	D F A C	preparation (subdominant)
V	G7	G B D F	tension (dominant: B–F tritone)
I	Cmaj7	C E G B	rest (tonic)

The bass leaps by fourths (D → G → C): the strongest motion in tonal harmony. But for the improviser, the secret is not in the bass: it lies in the guide tones.

Guide tones: thirds and sevenths

A chord's third and seventh are the notes that tell you whether it is major, minor or dominant. Root and fifth, on the other hand, are interchangeable from one chord to the next (and the bass player takes care of them). Look at what happens when you write only thirds and sevenths:

M:4/4
L:1/4
Q:1/4=80
K:C
%%staves {RH LH}
V:RH clef=treble
V:LH clef=bass
[V:RH] "Dm7" [Fc]4 | "G7" [FB]4 | "Cmaj7" [EB]4 | [EB]4 |]
[V:LH] D,4 | G,,4 | C,4 | C,4 |]

Magic: each voice moves by a half step at most, or stays put. C (7th of Dm7) falls to B (3rd of G7); F (3rd of Dm7) stays and becomes the 7th of G7, then falls to E (3rd of Cmaj7). This gliding is jazz voice-leading. If your improvisation sounds these notes as the chords change, the harmony draws itself, even with no accompaniment.

The golden rule: the 7th of a chord falls by step to become the 3rd of the next chord. C → B, then F → E. Sing these two lines: they are the backbone of every phrase over a ii–V–I.

A melodic line built on guide tones

M:4/4
L:1/8
Q:1/4=110
K:C
"Dm7" A2 c2 z c d c | "G7" B4 z2 A F | "Cmaj7" E8 |]

Bar 1: we lean on C (the 7th). Bar 2: we land on B (3rd of G7) exactly at the chord change, then slide towards F (the 7th). Bar 3: F resolves to E (3rd of Cmaj7). It is simple, singable and instantly "sounds jazz".

Exercise: the guide-tone path

Start the jazz track in C (a cycle of ii–V–Is).

Left hand alone. Play the guide tones as whole notes, as in the example: F+C, F+B, E+B. Stop looking at the score after a few rounds.
One note per chord. Right hand: one long note per chord, always a third or a seventh. Two possible paths: C → B → B, or F → F → E.
Guide tones on beat 1. Improvise freely with the notes of the C scale, but you must place a guide tone on the first beat of every bar.
Transpose. Do the same in F (Gm7 – C7 – Fmaj7) with the jazz track in F. Guide tones: B♭+F → B♭+E → A+E.

Common mistake: playing the C scale from start to finish and "hoping it works". Technically no note is wrong, but nothing makes the chord change audible. Listeners only perceive the harmony if you target the notes that change.

To hear the progression clearly, also train your ear with progression dictations.