Module 10: Improvisation II – Bebop LanguageLesson 4advanced⏱ 2 hours + four weeks of drills

Rhythm changes, form and vocabulary

The 32-bar rhythm changes form in Bb by numerals, the common substitutions, and original bebop lines for the A section, the bridge and the turnaround, with every chromatic note explained.

Why every jazz musician learns rhythm changes

After the blues, the chord progression of George Gershwin's "I Got Rhythm" is the most reused form in jazz. Dozens of bebop heads were written on it, it is called at every jam session, and it is the progression on which players learn to handle fast-moving ii–Vs, a cycle-of-fifths bridge and a turnaround every two bars. Nothing about it is exotic; what makes it hard is the speed, usually 180 to 260 bpm, and the fact that the chords change every two beats for most of the A section. You have to know the form so well that you never think about it, and you need vocabulary that fits the two-beat harmonic rhythm.

This lesson gives you the form in Roman numerals so that you can play it in any key, the substitutions you will hear from a rhythm section, and six original lines that cover the A section, the bridge and the turnaround. The harmonic devices come from the ii–V–I vocabulary lesson and the altered dominant lesson; if either is shaky, review it first. Reading the form from a chart was covered in reading chord charts.

The form: 32 bars, AABA

Rhythm changes is a 32-bar AABA form: an eight-bar A section played twice, an eight-bar bridge, and the A section once more. In Bb, the key almost everyone plays it in, the A section is:

Bars 1–4 are a turnaround played twice (I–VI–ii–V, with the iii chord standing in for I the second time). Bars 5–6 move to the IV chord through its own ii–V (Fm7 Bb7 is the ii–V of Eb) and then pass through the #iv diminished chord back towards the tonic. Bars 7–8 are the turnaround again, which sends you back to the top (first and second A) or on to the bridge. The last A ends on the tonic, so the final turnaround is usually replaced by two bars of Bbmaj7 or a I–VI–ii–V that resolves at the top of the next chorus.

The bridge is eight bars of dominant chords moving around the cycle of fifths, two bars each, starting on the dominant of the vi chord:

Memorise the form as numerals and as a story: turnaround, turnaround, to the IV and back, turnaround for the A, four dominants round the cycle for the bridge. Then play it in Bb until the chords are reflexes, and only after that in F and Eb.

Common substitutions

A rhythm section rarely plays the plain changes for a whole chorus. These are the substitutions you will hear most, with their numerals in Bb. Learn to recognise them by ear so that your lines agree with the bass.

The chord-tone checks on the lines below use the plain symbols except where the line is deliberately built on a substitute. The diminished and tritone substitutions in the table are spelled out here so that you can see the shared tones:

Lines for the A section

Rhythm changes vocabulary has to work in two-beat units: four eighth notes per chord. The lines below are built from the devices you know, two chords per bar, with each chord's four eighths starting on a chord tone. Tempo marked 160 for playback; real-world tempos are faster, so build them up gradually.

Line 1: bars 1–4

The turnaround twice, in 3rd position. Over each dominant the four notes are 3, b9, root, b7 (G7) or 3, 5, b7, b9 (F7), so that the b9 falls to the 5th of the next chord. Over the minor chords the 9th is the only colour.

\tempo 160
.
\ts 4 4
:8 3.2{ch "Bbmaj7"} 6.2 5.1 6.1 7.1{ch "G7"} 4.1 3.1 6.2 | 4.2{ch "Cm7"} 3.2 5.3 3.3 7.4{ch "F7"} 5.3 4.2 7.2 | 6.2{ch "Dm7"} 5.2 3.2 5.3 4.3{ch "G7"} 3.2 6.2 4.1 | 3.1{ch "Cm7"} 4.2 5.3 3.2 :4 7.4{ch "F7"} 6.2 |

Bar 1: Bbmaj7 arpeggio from the 3rd up to the root; G7: 3, b9, root, b7. Bar 2: Cm7 descending from the b3 through the 9th to the b7; F7: 3, 5, b7, b9. Bar 3: Dm7 descending from the b3 through the 9th; G7: 3, 5, b7, b9 ascending. Bar 4: Cm7: 5, b3, root, 9; F7: the 3rd and root as quarter notes, leaving space before the next phrase.

The line changes direction every two beats. That is the sound of rhythm changes at speed: short gestures that each outline one chord and hand over to the next with a half-step resolution.

Line 2: bars 5–8 and the downbeat of the next A

The second half of the A section: the ii–V to the IV chord, the IV and the #iv diminished, and the turnaround that leads back to the top. The Edim7 bar uses a descending diminished arpeggio whose last note (Db) steps up to D, the root of Dm7, the same half-step logic as the dominant resolutions. The line ends on the 5th of Bbmaj7 at the top of the next A.

\tempo 160
.
\ts 4 4
:8 6.4{ch "Fm7"} 5.3 4.2 3.1 4.1{ch "Bb7"} 6.2 7.3 4.3 | 3.3{ch "Ebmaj7"} 3.2 4.2 3.1 6.1{ch "Edim7"} 8.2 5.2 6.3 | 7.3{ch "Dm7"} 6.2 5.1 8.1 7.1{ch "G7"} 4.1 3.1 6.2 | 4.2{ch "Cm7"} 3.2 5.3 3.3 7.4{ch "F7"} 5.3 4.2 7.2 | :1 6.2{ch "Bbmaj7"} |

Bar 5: Fm7 arpeggio from the b3 to the 9th; Bb7 descending b7, 5, 3, b9. Bar 6: Ebmaj7: 5, 7, root, 3; Edim7 arpeggio descending from the b5 (Bb, G, E, Db). Bar 7: Dm7 arpeggio from the root; G7: 3, b9, root, b7. Bar 8: Cm7 from the b3 through the 9th; F7: 3, 5, b7, b9, resolving to the 5th of Bb.

Play Lines 1 and 2 back to back and you have a complete A section. Then play the A section three times with the bridge between the second and third, which is a full chorus.

Lines for the bridge

The bridge gives you two bars on each dominant, and the temptation is to run bebop dominant scales for eight bars. Resist it. The strongest bridge lines use the scale for a bar and an arpeggio or cell for the next, so that the two bars have a shape, and they save the altered colour for the last bar of each dominant where it points at the next chord.

Line 3: D7 and G7

The first half of the bridge in 3rd position. D7 gets a descending D bebop dominant run from the 5th and then an arpeggio; G7 gets a descending G bebop dominant run from the b7 and an ascending arpeggio that ends on the 13th.

\tempo 160
.
\ts 4 4
:8 5.1{ch "D7"} 3.1 7.2 5.2 3.2 6.3 5.3 4.3 | 7.4 7.3 7.2 5.1 8.1 5.1 7.2 7.3 | 6.2{ch "G7"} 5.2 3.2 5.3 4.3 7.4 5.4 4.4 | :8 5.4 4.3 3.2 6.2 :2 5.2 |

Bar 17: D bebop dominant from the 5th: 5, 11, 3, 9, root, major 7th, b7, 13. Downbeats: 5, 3, root, b7. Bar 18: D7 arpeggio from the 5th below the root up to the b7 and back down. Bar 19: G bebop dominant from the b7: b7, 13, 5, 11, 3, 9, root, major 7th. Downbeats: b7, 5, 3, root. Bar 20: G7 arpeggio from the root, landing on the 13th and holding it: a note that leans towards the coming C7.

Line 4: C7 and F7, back to the A

The second half, also in 3rd position, with the b9 as the colour note on each dominant. C7 descends its bebop dominant scale from the 3rd and then plays an arpeggio up to the b9 and back; F7 plays the 3-to-b9 arpeggio, then a 1-2-3-5 cell with the 13th as the turn at the top, and resolves to the root of Bbmaj7 at the top of the last A.

\tempo 160
.
\ts 4 4
:8 5.2{ch "C7"} 3.2 5.3 4.3 3.3 7.4 5.4 3.4 | 7.5 5.4 3.3 6.3 5.3 3.3 5.4 7.5 | 7.4{ch "F7"} 5.3 4.2 7.2 6.2 4.2 5.3 7.4 | 3.4 5.4 7.4 5.3 4.2 3.2 5.3 7.4 | :1 3.3{ch "Bbmaj7"} |

Bar 21: C bebop dominant from the 3rd: 3, 9, root, major 7th, b7, 13, 5, 11. Downbeats: 3, root, b7, 5. Bar 22: C7: 3, 5, b7, b9, root, b7, 5, 3. Downbeats: 3, b7, root, 5. Bar 23: F7: 3, 5, b7, b9, then root, b7, 5, 3. Downbeats: 3, b7, root, 5. Bar 24: F7: root, 9, 3, 5, b7, 13, 5, 3. Downbeats: root, 3, b7, 5. The last 3rd rises a half step to the tonic.

Bars 22 and 23 are the same gesture on two chords a 4th apart, which is the kind of sequence that makes a bridge sound planned. The next lesson on your own lines treats sequences systematically.

Turnaround vocabulary

The turnaround is two bars that occur four times per chorus (bars 1–2, 3–4, 7–8 and 31–32, with the iii chord in place of I in some of them). Having several ways to play it is what keeps a rhythm changes solo from repeating itself. Here are two.

Turnaround 1: plain changes, 5th position

The I chord arpeggio from the 3rd to the 9th; G7 from the 5th to the 3rd and up to the b9; Cm7 from the 5th down to the 9th; F7 from the 3rd through the b9 to the b7, resolving to the 3rd of Bb.

\tempo 160
.
\ts 4 4
:8 7.3{ch "Bbmaj7"} 6.2 5.1 8.1 10.1{ch "G7"} 7.1 6.2 9.2 | 8.2{ch "Cm7"} 8.3 10.4 7.3 5.1{ch "F7"} 7.2 6.2 8.3 | :1 7.3{ch "Bbmaj7"} |

Turnaround 2: tritone substitutes

Both dominants replaced by their tritone substitutes, Db7 for G7 and B7 for F7, so the bass descends chromatically Bb–Db–C–B–Bb. The line plays each substitute's arpeggio straight, descending from the b7, and every note is a chord tone of the symbol in force. Against a rhythm section playing the plain changes the same notes sound as the b5, b9, 3 and b7 of G7 and F7, which is why this turnaround is heard so often in bebop.

\tempo 160
.
\ts 4 4
:8 3.2{ch "Bbmaj7"} 6.2 5.1 6.1 7.1{ch "Db7"} 4.1 6.2 6.3 | 5.3{ch "Cm7"} 4.2 3.1 6.1 5.1{ch "B7"} 7.2 4.2 4.3 | :1 3.3{ch "Bbmaj7"} |

Note that Turnaround 2 fits whether the rhythm section plays G7 and F7 or Db7 and B7, but Turnaround 1 clashes with a bass player who plays the substitutes (its natural 5ths of G7 and F7 collide with the substitute roots). When you cannot hear what the bassist is doing, the tritone-sub line is the safer choice.

Playing a chorus

Assemble a chorus from the material: Line 1 and Line 2 for the first A; Turnaround 1 and your own playing for the second A; Lines 3 and 4 for the bridge; Turnaround 2 and Line 2's bars 5–8 for the last A. Then start replacing the written lines with your own, two beats at a time, keeping the rule that each two-beat unit begins on a chord tone and ends on a note that resolves by step into the next chord.

Three things to watch at tempo:

• Form. Count the A sections. Losing your place in the second A is the classic rhythm changes error; the bridge arriving a bar early or late is the giveaway. Practise with a backing track or a recording and say "bridge" out loud as bar 17 arrives.
• Economy. At 220 bpm you cannot play eight eighths on every chord and make sense. Leave the second half of a bar empty, play quarter notes for two bars, let a 13th ring across a chord change. Line 1 ends with two quarter notes for exactly this reason.
• The bridge is the release. After sixteen bars of two-beat changes, eight bars of dominants feel spacious. Use longer phrases, more range, and save the altered colour for the last bar of each dominant.

Exercises

1. Form from memory. Play the chord roots of the whole 32 bars as quarter notes at 120 bpm, saying the numerals. Then in F and Eb.
2. Two-beat cells. Over bars 1–4 looped, play only four-note cells that begin on the 3rd of each chord. Then only cells that begin on the root. Then alternate.
3. Bridge with related iis. Play Lines 3 and 4 over the bridge with the related ii chords added (Am7 D7 | Dm7 G7 | Gm7 C7 | Cm7 F7, one bar each); the bebop-dominant bars already fit the ii chords (the scale is shared, as the bebop scales lesson showed).
4. Turnaround variations. Write two more two-bar turnaround lines: one over Bb6 Bdim7 | Cm7 C#dim7 and one over Dm7 G7alt | Cm7 F7alt. Check every note, then play them in F.
5. Full choruses. With a backing track at 160, play the assembled chorus above, then one chorus of your own; record both and listen for the bridge entry and for two-beat units that do not start on a chord tone.

Quiz