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 G♭7 – B7 – C°7 – E♭7 – A♭m7 – D♭7. In G♭ the blues is G♭7, B7 and D♭7 at heart; jazz players add C°7 in bar 6 (bass C climbing back to G♭), E♭7 in bar 8 to set up the A♭m7 – D♭7 cadence, and a G♭7 E♭7 | A♭m7 D♭7 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 · G♭7 with Mixolydian
Guitar · standard tuning
Piano · B7 with Mixolydian
Guitar · standard tuning
Piano · C°7 with Diminished (whole–half)
Guitar · standard tuning
Piano · E♭7 with Mixolydian
Guitar · standard tuning
Piano · A♭m7 with Dorian
Guitar · standard tuning
Piano · D♭7 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.
Your next 10 minutes
At 60 bpm, first find these chord roots: G♭, B, C, E♭, A♭, D♭. Then play or sing the root of each sounding chord as you follow the trainer. Keep counting through the whole form. If you lose your place, return to roots before adding notes.
G♭7: B♭ and F♭; B7: D♯ and A; C°7: E♭ and B𝄫; E♭7: G and D♭; A♭m7: C♭ and G♭; D♭7: F and C♭. Choose one voice and move to the nearest third or seventh in the next chord. Use your ear; not every transition is a half step.
Using the chords G♭7, B7, C°7, E♭7, A♭m7, D♭7, use only chord tones for one chorus. On the next chorus add a single passing note between targets. Repeat one rhythmic idea, then leave a full bar of space.
Listen for this: Resolve into G♭7 without rushing. Success means keeping the form and hearing your next target, not reaching the highest tempo.
Understand the sound
The blues keeps its twelve-bar identity even as the harmony becomes richer. Count the bars first; the passing diminished chord and turnaround should not make you lose the return to I.
| Chord change | One possible line | Movement |
|---|---|---|
| G♭7 → B7 | F♭ → D♯ | Down 1 semitone |
| B7 → G♭7 | A → B♭ | Up 1 semitone |
| B7 → C°7 | A → B𝄫 | Hold the same pitch |
| C°7 → G♭7 | B𝄫 → B♭ | Up 1 semitone |
| G♭7 → E♭7 | F♭ → G | Up 3 semitones |
Play the first pitch in each row during its chord, then move to the target as the next chord begins. Choose an octave that allows the indicated movement. Sing the line once before playing it; add the bass roots only after the upper voice feels secure.
Stop playing for one complete cycle while you keep counting. Re-enter on G♭7. If you miss the entrance, simplify to roots and work at 60 bpm before adding passing notes.
Reference
| Function | Chord | Chord tones (1–3–5–7) | Chord-scale | Scale notes |
|---|---|---|---|---|
| I⁷ | G♭7 | G♭ – B♭ – D♭ – F♭ | Mixolydian | G♭ A♭ B♭ C♭ D♭ E♭ F♭ |
| IV⁷ | B7 | B – D♯ – F♯ – A | Mixolydian | B C♯ D♯ E F♯ G♯ A |
| ♯iv°⁷ | C°7 | C – E♭ – G♭ – B𝄫 | Diminished (whole–half) | C D E♭ F G♭ A♭ A B |
| VI⁷ | E♭7 | E♭ – G – B♭ – D♭ | Mixolydian | E♭ F G A♭ B♭ C D♭ |
| ii⁷ | A♭m7 | A♭ – C♭ – E♭ – G♭ | Dorian | A♭ B♭ C♭ D♭ E♭ F G♭ |
| V⁷ | D♭7 | D♭ – F – A♭ – C♭ | Mixolydian | D♭ E♭ F G♭ A♭ B♭ C♭ |
| Guide tones | G♭7 | B7 | C°7 | E♭7 | A♭m7 | D♭7 |
|---|---|---|---|---|---|---|
| 3rd | B♭ | D♯ | E♭ | G | C♭ | F |
| 7th | F♭ | A | B𝄫 | D♭ | G♭ | C♭ |
How to practise this
1. Arpeggios in time. Loop the vamp at 70–90 bpm and play G♭7, B7, C°7, E♭7, A♭m7, D♭7 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♭ → D♯–A → E♭–B𝄫 → G–D♭ → C♭–G♭ → F–C♭. Notice that C♭, the 7th of D♭7, moves to B♭, the 3rd of G♭7 — that is the resolution.
3. Chord-scales. Run Mixolydian on G♭7, Mixolydian on B7, Diminished (whole–half) on C°7, Mixolydian on E♭7, Dorian on A♭m7, Mixolydian on D♭7, then improvise keeping chord tones on beats 1 and 3.
4. Move it. When G♭ is clean, go to B major — a fourth up — and keep going around the circle.
Take it to the bandstand.Practice Radio streams this form and every other progression through all twelve keys, with the chord and scale shown live — plus ear-training and call & response modes.
▶ Open Practice RadioCommon questions
G♭7 – B7 – C°7 – E♭7 – A♭m7 – D♭7. The I7 chord is G♭7 (G♭, B♭, D♭, F♭); The IV7 chord is B7 (B, D♯, F♯, A); The ♯iv° chord is C°7 (C, E♭, G♭, B𝄫); The VI7 chord is E♭7 (E♭, G, B♭, D♭); The ii chord is A♭m7 (A♭, C♭, E♭, G♭); The V chord is D♭7 (D♭, F, A♭, C♭).
G♭7: Mixolydian (G♭ A♭ B♭ C♭ D♭ E♭ F♭). B7: Mixolydian (B C♯ D♯ E F♯ G♯ A). C°7: Diminished (whole–half) (C D E♭ F G♭ A♭ A B). E♭7: Mixolydian (E♭ F G A♭ B♭ C D♭). A♭m7: Dorian (A♭ B♭ C♭ D♭ E♭ F G♭). D♭7: Mixolydian (D♭ E♭ F G♭ A♭ B♭ C♭).
The thirds and sevenths: B♭ and F♭ over G♭7, D♯ and A over B7, E♭ and B𝄫 over C°7, G and D♭ over E♭7, C♭ and G♭ over A♭m7, F and C♭ over D♭7. Connect each voice to the nearest available third or seventh of the next chord; the distance depends on the progression and voicing.
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, B Mixolydian, C Dim. W–H, E♭ Mixolydian, A♭ Dorian, D♭ Mixolydian.