Module 11: Harmony II: substitution and reharmonisationLesson 1advanced⏱ 90 min + two weeks of daily practice

Secondary dominants and related ii chords

Learn to find the dominant of any diatonic chord, put its related ii chord in front of it, chain dominants backwards through the cycle, and recognise all of this in the standards you already play.

Why a key has more than one dominant

A dominant seventh chord does one thing: it points at the chord a perfect 5th below it. In Module 3 you met the dominant of the tonic, V7, and the ii–V–I it belongs to. But any chord that is stable enough to be heard as a temporary home can be given a dominant of its own. In C major, Dm7 can be preceded by A7, Fmaj7 by C7, G7 by D7, Am7 by E7. Each of these is a secondary dominant: a dominant seventh chord that points at a diatonic chord other than the tonic. They are written V7/ii ("five-seven of two"), V7/IV, V7/V and V7/vi, and together with their related ii chords they account for most of the non-diatonic chords in a Great American Songbook tune. Once you can see them, a 32-bar chart that looked like a wall of random symbols turns into a few diatonic chords with short detours in front of them.

Finding the five secondary dominants

Take the diatonic seventh chords of C major from the diatonic sevenths lesson. Five of them can be targets: ii, iii, IV, V and vi. Build a dominant seventh a perfect 5th above the root of each target and you have its secondary dominant.

In order these are V7/ii (A7), V7/iii (B7), V7/IV (C7), V7/V (D7) and V7/vi (E7). Two things are missing from the list on purpose:

• There is no V7/I. The dominant of the tonic is simply V7, the one you already know.
• There is no V7/vii. The diatonic chord on the 7th degree is half-diminished, too unstable to be a temporary home, so nobody writes a dominant for it.

Compare the table with the diatonic chords of C and notice that each secondary dominant introduces one or two notes from outside the key. A7 brings C#, the leading tone of D; B7 brings D# and F#, the leading tone and the 5th of E; D7 brings F#, the leading tone of G; E7 brings G#, the leading tone of A. C7 is the odd one out: C major already contains all of its notes except Bb, which is not a leading tone but the 7th that pulls down to the 3rd of F. The foreign note is the whole point. It is what makes the ear expect the target chord, and it is the note you should bring out when you solo over a secondary dominant.

Here are all five in every key. You will not memorise this table by reading it; you will memorise it by playing the exercises below through the cycle.

A faster way to find them than the table: the root of V7/x is a perfect 5th above the root of x, or, equivalently, a perfect 4th below it. V7/V is always built on the 2nd degree of the key, V7/ii on the 6th, V7/vi on the 3rd, V7/IV on the tonic itself, and V7/iii on the 7th degree. Say those five sentences out loud until they are automatic.

Hearing and voicing V7/ii: the iii–VI7–ii–V turnaround

The most common secondary dominant by a wide margin is V7/ii, because the ii–V–I is everywhere and composers love to prepare the ii. Put A7 in front of Dm7 in C and you get the turnaround iii–VI7–ii–V–I, which opens or closes hundreds of standards. Here it is with drop-2 shapes on strings 5–4–3–2, voice-led so that every voice moves by step or by a minor 3rd at most. Compare the A7 with the Am7 you would expect in a purely diatonic I–vi–ii–V: a single note, C raised to C#, turns the minor chord into a dominant that leans towards D.

\tempo 100
.
\ts 4 4
:1 (3.5 5.4 4.3 5.2){ch "Cmaj7"} | :2 (5.5 5.4 4.3 5.2){ch "Em7"} (4.5 5.4 2.3 5.2){ch "A7"} | (5.5 7.4 5.3 6.2){ch "Dm7"} (5.5 5.4 4.3 6.2){ch "G7"} | :1 (3.5 5.4 4.3 5.2){ch "Cmaj7"} |

Play the example, then replace the A7 with Am7 (the same shape with the 3rd-string note a fret lower) and play it again. The second version is pleasant and static; the first one moves. That is the whole argument for secondary dominants in four bars.

Here is the same idea in every key. Play it through the cycle of fourths with the shapes above, moving the whole set of four to each new tonic.

V7/IV and V7/V: the tonic turns dominant, the ii turns major

The second most common secondary dominant is V7/IV. It is special because it is the tonic chord with a lowered 7th: Cmaj7 becomes C7 and suddenly the most stable chord in the key wants to move to F. You hear this at the end of the first A section of many AABA tunes (the tonic goes to I7 and the next phrase starts on IV), and in bar 4 of every blues, where I7 becomes the dominant of the IV7 in bar 5 (see the jazz blues lesson).

V7/V is the dominant built on the 2nd degree: in C it is D7, the ii chord with a raised 3rd. The classic place to find it is a bridge or a turnaround where ii7–V7 becomes II7–V7, a chain of two dominants.

The example below puts both into one phrase with drop-3 shapes on strings 6–4–3–2, the Joe Pass style you learned in the drop-3 lesson. The bass note stays on the 8th fret for four bars while the chord above it changes, which is a good way to hear what a single altered note does.

\tempo 80
.
\ts 4 4
:1 (8.6 9.4 9.3 8.2){ch "Cmaj7"} | (8.6 8.4 9.3 8.2){ch "C7"} | (8.6 7.4 9.3 6.2){ch "Fmaj7"} | (8.6 7.4 7.3 7.2){ch "D7"} | (7.6 5.4 7.3 6.2){ch "G7"} | (7.6 5.4 5.3 5.2){ch "Cmaj7"} |

The related ii chord

Any dominant can be preceded by its own ii chord, which gives a complete ii–V pointing at the target. The related ii of a secondary dominant is the ii chord of the key the target lives in: a minor seventh built a perfect 4th below the dominant (or a whole step above the target). In C, the related ii of C7 (V7/IV) is Gm7, of D7 (V7/V) is Am7, of A7 (V7/ii) is Em7, which you already played above. The chart writes Gm7 C7 | Fmaj7 and your ear hears a short visit to the key of F. The table shows the two most useful related ii–V pairs in the common keys; work them out for the remaining keys yourself from the rule.

When the target is a minor chord (ii, iii or vi), you have a choice. The diatonic related ii is half-diminished, because that is the ii chord of a minor key (Module 3, minor-key harmony): in C, the related ii of E7 (V7/vi) is Bm7b5, giving Bm7b5 E7 | Am7. Many players and arrangers use a plain minor seventh instead (Bm7 E7 | Am7), which sounds brighter and is what you will find on a lot of charts. Both are correct; the half-diminished version is darker and more "minor".

The next example chains related ii–V pairs through C on the top four strings: a ii–V to IV, a ii–V to V (which lands on G7, the real dominant, so it just continues into the home ii–V), and the home ii–V–I. The phrase is six bars long and it is one of the most useful comping etudes you will ever learn, because it is the harmonic skeleton of a huge number of A sections.

\tempo 110
.
\ts 4 4
:1 (5.4 5.3 5.2 7.1){ch "Cmaj7"} | :2 (5.4 7.3 6.2 6.1){ch "Gm7"} (5.4 5.3 5.2 6.1){ch "C7"} | :1 (3.4 5.3 5.2 5.1){ch "Fmaj7"} | :2 (5.4 5.3 5.2 5.1){ch "Am7"} (4.4 5.3 3.2 5.1){ch "D7"} | (3.4 5.3 3.2 5.1){ch "Dm7"} (3.4 4.3 3.2 3.1){ch "G7"} | :1 (2.4 4.3 1.2 3.1){ch "Cmaj7"} |

Notice the pattern in the fingering: each ii–V pair is a minor seventh shape followed by the dominant shape with the same bass note or one fret away. In the voice-leading lesson you learned that a ii7 in one inversion and its V7 in the next inversion share two notes; here you see that this holds for every ii–V pair, diatonic or secondary, because it is a property of the two chord qualities and not of the key.

Backcycling: a chain of dominants

If a dominant can have a dominant, then that dominant can have one too. Start on the tonic and go backwards: C is preceded by G7, G7 by D7, D7 by A7, A7 by E7. Writing it forwards gives E7 | A7 | D7 | G7 | C, four dominants in a row, each resolving into the next. This is called backcycling or an extended dominant chain, and it is the harmony of the bridge of rhythm changes (III7–VI7–II7–V7), of the first eight bars of several Ellington and Porter tunes, and of countless turnarounds. Each chord in the chain is a secondary dominant of the next one, and the only chord that has to be in the key is the last one.

\tempo 90
.
\ts 4 4
:1 (7.5 9.4 7.3 9.2){ch "E7"} | (7.5 7.4 6.3 8.2){ch "A7"} | (5.5 7.4 5.3 7.2){ch "D7"} | (5.5 5.4 4.3 6.2){ch "G7"} | (3.5 5.4 4.3 5.2){ch "Cmaj7"} |

Look at what the voice leading does. From E7 to A7 the bass note stays and the 3rd of E7 becomes the 7th of A7 while the 7th of E7 becomes the 3rd of A7: exactly the guide-tone exchange you learned for ii–V, applied between two dominants. The whole chain works because every dominant's guide tones resolve into the next dominant's guide tones by half step, and that is also why you can play one shape and slide it around: the hand learns the chain faster than the head does.

Add the related ii to each dominant in the chain and you get the full version: Bm7b5 E7 | Am7 D7 | Dm7 G7 | Cmaj7, or with the diatonic related iis of the inner chords, F#m7b5 B7 | Em7 A7 | Dm7 G7 | Cmaj7. This second one is the harmony of the last eight bars of a well-known Rodgers and Hart ballad, and recognising it will save you from ever having to memorise those bars chord by chord.

\tempo 100
.
\ts 4 4
:2 (9.5 10.4 9.3 10.2){ch "F#m7b5"} (9.5 9.4 8.3 10.2){ch "B7"} | (7.5 9.4 7.3 8.2){ch "Em7"} (7.5 7.4 6.3 8.2){ch "A7"} | (5.5 7.4 5.3 6.2){ch "Dm7"} (5.5 5.4 4.3 6.2){ch "G7"} | :1 (3.5 5.4 4.3 5.2){ch "Cmaj7"} |

Soloing over secondary dominants

A secondary dominant is a dominant, so everything you know about playing on V7 applies, in the key of the target. The one note to aim for is the note that is foreign to the home key: the 3rd of the secondary dominant. If you are playing on A7 in C, the C# is what tells the listener that this is not Am7, and landing on it on a strong beat makes the whole chord audible even without a rhythm section. The 7th of the secondary dominant resolves down a half step to the 3rd of its target, exactly as in a ii–V–I.

Because the target of V7/ii is a minor chord, A7 in C is usually played with a b9 (the Bb is the b6 of D minor, the key you are briefly in), and the same is true of V7/vi (E7b9) and V7/iii (B7b9). Dominants pointing at major chords (V7/IV and V7/V) usually take the natural 9 and 13. This is the same rule as in minor-key harmony: a dominant borrows its tensions from the key of its target.

\tempo 120
.
\ts 4 4
:8 5.3{ch "Cmaj7"} 5.2 8.2 7.1 8.1 7.1 8.2 5.2 | 7.3{ch "Em7"} 4.3 5.4 7.5 7.4{ch "A7b9"} 6.3 5.2 6.1 | 5.1{ch "Dm7"} 6.2 7.3 5.3 6.2{ch "G7"} 4.3 7.3 5.4 | :4 5.2{ch "Cmaj7"} 5.3 :2 r |

Practise this line, then write your own over the same changes with one rule: beat 1 of each new chord is the 3rd of that chord. In the second week, do the same over the six-bar chained ii–V example.

Finding them in standards

The quickest way to make this lesson permanent is to go through the tunes you already know and label every dominant chord as V7, V7/ii, V7/IV, V7/V or V7/vi (and every minor seventh before one of them as a related ii). A few places to look, described in Roman numerals so that you can check them in any key:

• Rhythm changes, A section: I–VI7–ii–V7 (VI7 is V7/ii) in bars 1–2, and in bars 5–6 the tonic becomes I7 (V7/IV) and goes to IV. The bridge is pure backcycling: III7–VI7–II7–V7, two bars each.
• The jazz blues: I7 in bar 4 is V7/IV, and VI7 in bar 8 is V7/ii, which makes bars 8–10 a VI7–ii–V.
• Ballads with a I–VI7–ii–V turnaround at the end of each eight: the VI7 is V7/ii.
• Tunes that start on II7: a II7–V7–I opening is V7/V resolving to V7, and the related ii of the II7 is the vi chord of the key.
• Any ii–V that does not resolve to I is almost always a related ii–V aimed at IV, at vi or at a new key.

Label ten tunes this way and you will find that only a small number of chords in each remain unexplained; those are the ones the next four lessons deal with.

Exercises

1. Say the five. For each of the twelve keys, say the five secondary dominants out loud in the order V7/ii, V7/iii, V7/IV, V7/V, V7/vi, then check against the table. Time yourself; under 15 seconds per key is the goal.
2. Turnaround through the cycle. Play Imaj7 | iii7 VI7 | ii7 V7 | Imaj7 with the drop-2 shapes in all twelve keys, moving round the cycle of fourths. Two bars per chord at first, then the written rhythm.
3. V7/IV and V7/V in drop 3. Play the six-bar drop-3 example in C, F, Bb and G. Keep the bass on the 6th string throughout.
4. Related iis. Play the six-bar chained ii–V etude on strings 4–3–2–1, then rebuild it on strings 5–4–3–2 with your own nearest inversions. Say the function of each chord as you play it ("two of four, five of four, four...").
5. Backcycle. Play E7 | A7 | D7 | G7 | C in three string sets, then add the related iis. Then start the chain on different dominants: B7 | E7 | A7 | D7 | G7 | C is a five-chord backcycle.
6. Chart analysis. Label every dominant in three standards you know with its function. Bring the list to the next lesson; tritone substitution will explain some of the leftovers.

Quiz