Have you ever ridden on a roller coaster blindfolded? That’s how it feels to improvise without understanding internal modulation. It’s like driving through a thick London fog. Progress is halting, movements are uncertain and tense.
By contrast, the player who understands how to navigate key changes improvises smoothly and confidently.
This month, we learn to recognize an internal modulation and craft an effective response.
Here’s how some students describe page 18 of Real Book 1: “’All the Things You Are’ is clearly in concert Ab major throughout, and 14 of its 36 measures have accidentals.” In reality, “All the Things” traverses through 6 different keys in those 36 bars, but it has only 3 accidentals! More on that in a moment.
At a jam session, it is easy to spot the “non-mod players” (those unaware of internal modulations). They inevitably scuffle and lose their Trane of thought at the moment of modulation.
By contrast, improvisers who understand how key changes work navigate smoothly through those rough waters.
1.) “On Green Dolphin Street”
Figure 1 shows bars 9-16 of “On Green Dolphin Street.” The first 4 bars employ a ii-V-I  See last month’s article for details on the ii-V-I progression progression in concert Eb.  We’ll refer to concert key throughout, since saxophones come in 2 or 3 different keys. If you are planning on frequenting jam sessions, it’s critical you get in the habit of speaking in terms of the concert key. The next 3 bars feature the same progression in Gb, while bars 16 and 17 return to the home key with another ii-V-I in Eb. Note that the melody in bars 13-15 is a mirror image of the theme introduced in bars 9-11. The only difference is that this theme has been transposed from Eb to Gb. This device is known as a “sequence,” and it is an excellent tool for adding unity, variety, and coherence to your improvisations. The syllables in each case are: so re mi fa so le te so. LE and TE are accidentals, the b9 and #9 respectively of the V7 chord.
Figure 2 shows how you might use “the scale of the moment” – the scale which fits “the key of the moment” – to create an improvised line which is both logical and melodically pleasing, and which accurately reflects the chord changes and the key changes resulting from those chords. Notice that it is the ii-V-I progression which causes the modulation.
2.) “Body and Soul”
Almost every great tenor player from Coleman Hawkins on down the line has weighed in on “Body and Soul.” Are you comfortable playing the bridge? (One student, a fine trombonist, quipped, “If I don’t know the bridge, I just tell the tenor player to take it!”)
Verse 2 ends with a ii-V-I progression in the home key of concert Db. As if it were an afterthought, the last 2 beats of bar 16 introduce a quick ii-V in the new key of D, which is up a half step from the home key of Db. This key change is shown in Figure 3.
The Db melody note which ends verse 2 is suddenly transformed from DO to TI. You can think of that transition as “DO=>TI” or “the old DO becomes the new TI.” Then the bridge melody begins with the new DO, which is a D natural
Figure 4 shows how you might use these 2 scales in your improv to help delineate the key change.
By looking at the syllables under the melody notes, you’ll notice there are only 2 accidentals, the passing note RI at the end of bar 16 and the LE which ends bar 17. (Actually, Coltrane would likely think of the Gm7-C7 as a quick ii-V in the key of F, as shown in the figure. He would accentuate this very brief foray into the key of F with a suitable scale or arpeggio highlighting that momentary tonal center.)
3.) “How High the Moon”
Charlie Parker used the changes  the chord progression accompanying any tune is referred to as its “chord changes,” or simply as “the changes.” from “How High the Moon” to create his tune “Ornithology.” Both tunes are widely played by jazz musicians. Figure 5 shows the first 8 bars of “How High.”
Do you notice how this tune sequences down a whole step, using the identical theme each time? The syllables below the melody indicate the moment when the transposition from G major to F major occurs, when the Bb is transformed from ME to FA (ME=>FA). What causes this transformation? It is the ii‑V‑I in F highlighted with a red box in Figure 5. Can you hear that key change?
One way to visualize this transformation is to think of a French citizen crossing the border into Italy. On one side of the border, he is a citizen; on the other, he is a visitor. He cannot vote or hold office in Italy. He is still the same person; only his role has changed. This describes the fate of the Bb in bar 3. It is transformed by virtue of its accompanying harmonic environment from sounding and behaving like ME to sounding and behaving like FA, the way I sound after a glass of merlot.
Figure 6 shows how you might use this knowledge to create an improvisation which accurately reflects that modulation and exploits it to create a dynamic melodic statement.
4.) “All the Things You Are”
As noted above, “All the Things You Are” migrates through 6 different keys during its 36-bar form. The first modulation occurs at bar 5, as shown in Figure 7.
From 4 flats to none is a sure recipe for a homeless musician, if you aren’t packed and ready to go, before the rent comes due! Figure 8 suggests one of the countless ways you might successfully navigate this transition.
A word about how you might choose pitches for a moment like this may prove helpful. The F and Db are the third and root of the IV chord. The G natural was chosen to emphasize that the Db major7 chord is a IV chord in Ab, not a 1 chord in Db. As the modulation occurs, it is effective to choose a “common tone,” a pitch found in both keys. F is LA in Ab, and it is also FA in C. This, incidentally, was the melody note chosen by Jerome Kern, probably for that reason. I find the shorthand “LA=>FA” (the old LA becomes the new FA) an immensely helpful way to quickly grasp this key change.
The Ab and G are the b9 and root of the G7(b9) chord. B natural is what we refer to as “the sweet note” for 2 reasons. Number 1, it is the third of the chord, always a good choice. Number 2, in modulating from 4 flats to zero flats, the senior flat is Bb, the first to arrive at the party and the last to leave. If there is no Bb, then there will be no other flats. E natural is stressed in this measure for the same reason: It is the second flat in the pecking order. In bars 7 and 8, the B and the A are the major 7th and the 6th in the C chord, while the G# adds a bit of exotic spice.
Notice also how I used a repeated rhythmic motif (“bob-a-do-bup-baw”) to tie the line together.
5.) “What’s New”
In “What’s New,” Bob Haggart doesn’t waste any time: He hits us with a key change in bar 2! I bet that was new in 1939. Dexter Gordon still dug it in 1959, and many other jazz greats have included it on their set lists.
Once again, it is the ii‑V‑I progression which brings about the key change from C to Ab, a gain of 4 flats. As indicated in Figure 9, I suggest you conceptualize this modulation as “DO=>MI,” or “the old DO becomes the new MI.” Figure 10 presents one possible approach to improvising over this phrase.
Notice that the last 7 beats present an identical sequenced restatement of beats 2-8 (in the new key).
Looking at the rhythmic flow, we see quite a bit of variety here. At a slow ballad tempo like this, there is a lot of space. A player like Miles would leave that space alone, whereas Coltrane might utilize a “machine gun” approach. By contrast, Sonny Stitt favored quick starts and stops as illustrated here, while Paul Desmond’s rhythmic flow was much smoother. These are some choices you must grapple with, as you develop your style, formulate your preferences, and choose which statements you wish to make.
Regarding note choices, most of the notes in this passage are what we refer to as “chord tones,” tones found in each chord. In Figure 10, chord degrees are noted as R=root, 3,5,6, or 7. The six “non-harmonic tones” (notes not found in the chord) are marked as P=passing tone or N=neighbor tone.
In looking at “What’s New,” you will notice also that the bridge is a mirror copy of the verse, with the home key changed from C major to F major. This duplication adds unity to the piece and makes it far easier to memorize. Always be on the lookout for repetition such as this.
By the way, Miles Davis mistakenly played Benny Carter’s “When Lights Are Low” with a bridge formed the same way. That was a shame, as Carter’s original bridge was far superior. Both versions are presented in The Real Book.
This brief lesson has presented several examples of internal key changes, all of them initiated by ii-V-I progressions. Cultivate the habit of watching and listening for these patterns, and you will be way ahead of the game in terms of choosing notes appropriate to the “key of the moment.”
 See last month’s article for details on the ii-V-I progression.
 We’ll refer to concert key throughout, since saxophones come in 2 or 3 different keys. If you are planning on frequenting jam sessions, it’s critical you get in the habit of speaking in terms of the concert key.
 the chord progression accompanying any tune is referred to as its “chord changes,” or simply as “the changes.”