Jazz blues · G major
This is the 12-bar jazz blues form with the ♯iv°7, VI7 and ii–V turnaround that jazz players add to the plain blues — in G, the chords are G7 – C7 – C♯°7 – E7 – Am7 – D7. In G the blues is G7, C7 and D7 at heart; jazz players add C♯°7 in bar 6 (bass C♯ climbing back to G), E7 in bar 8 to set up the Am7 – D7 cadence, and a G7 E7 | Am7 D7 turnaround in the last two bars.
The form
12-bar chorus
Generic form in Roman numerals — the harmonic skeleton, not any particular tune. Two chords in a bar are two beats each.
Interactive trainer
Piano · G7 with Mixolydian
Guitar · standard tuning
Piano · C7 with Mixolydian
Guitar · standard tuning
Piano · C♯°7 with Diminished (whole–half)
Guitar · standard tuning
Piano · E7 with Mixolydian
Guitar · standard tuning
Piano · Am7 with Dorian
Guitar · standard tuning
Piano · D7 with Mixolydian
Guitar · standard tuning
Click any chord card to see its scale, and tap any key or fret to hear that note. Turn on “+ Arpeggios” or “+ Scales” and the guitar or piano plays the line live over the vamp, lighting each note on the diagram as it sounds. All audio is synthesized in your browser — nothing is recorded or copyrighted.
Reference
| Function | Chord | Chord tones (1–3–5–7) | Chord-scale | Scale notes |
|---|---|---|---|---|
| I⁷ | G7 | G – B – D – F | Mixolydian | G A B C D E F |
| IV⁷ | C7 | C – E – G – B♭ | Mixolydian | C D E F G A B♭ |
| ♯iv°⁷ | C♯°7 | C♯ – E – G – B♭ | Diminished (whole–half) | C♯ D♯ E F♯ G A A♯ C |
| VI⁷ | E7 | E – G♯ – B – D | Mixolydian | E F♯ G♯ A B C♯ D |
| ii⁷ | Am7 | A – C – E – G | Dorian | A B C D E F♯ G |
| V⁷ | D7 | D – F♯ – A – C | Mixolydian | D E F♯ G A B C |
| Guide tones | G7 | C7 | C♯°7 | E7 | Am7 | D7 |
|---|---|---|---|---|---|---|
| 3rd | B | E | E | G♯ | C | F♯ |
| 7th | F | B♭ | B♭ | D | G | C |
How to practise this
1. Arpeggios in time. Loop the vamp at 70–90 bpm and play G7, C7, C♯°7, E7, Am7, D7 as 1–3–5–7 quarter notes, one chord per bar. Use the “+ Arpeggios” loop above to hear it played and copy the line.
2. Guide tones. Play only the 3rd and 7th of each chord: B–F → E–B♭ → E–B♭ → G♯–D → C–G → F♯–C. Notice that C, the 7th of D7, falls a half-step to B, the 3rd of G7 — that is the resolution.
3. Chord-scales. Run Mixolydian on G7, Mixolydian on C7, Diminished (whole–half) on C♯°7, Mixolydian on E7, Dorian on Am7, Mixolydian on D7, then improvise keeping chord tones on beats 1 and 3.
4. Move it. When G is clean, go to C major — a fourth up — and keep going around the circle.
Common questions
G7 – C7 – C♯°7 – E7 – Am7 – D7. The I7 chord is G7 (G, B, D, F); The IV7 chord is C7 (C, E, G, B♭); The ♯iv° chord is C♯°7 (C♯, E, G, B♭); The VI7 chord is E7 (E, G♯, B, D); The ii chord is Am7 (A, C, E, G); The V chord is D7 (D, F♯, A, C).
G7: Mixolydian (G A B C D E F). C7: Mixolydian (C D E F G A B♭). C♯°7: Diminished (whole–half) (C♯ D♯ E F♯ G A A♯ C). E7: Mixolydian (E F♯ G♯ A B C♯ D). Am7: Dorian (A B C D E F♯ G). D7: Mixolydian (D E F♯ G A B C).
The thirds and sevenths: B and F over G7, E and B♭ over C7, E and B♭ over C♯°7, G♯ and D over E7, C and G over Am7, F♯ and C over D7. Each voice moves by a half-step or stays put — that is what makes the progression sound like it resolves.
Loop the vamp at a slow tempo, play each arpeggio 1–3–5–7 in time, then play each chord-scale up and down, then improvise using only chord tones on the strong beats. When it is clean, move to the next key around the circle of fourths.
All twelve keys
Related in G: ii–V–I · turnaround · rhythm changes. Read the theory in Chord-scale theory, or see the scales on their own pages: G Mixolydian, C Mixolydian, C♯ Dim. W–H, E Mixolydian, A Dorian, D Mixolydian.