Deciphering Jazz Chord Symbols

Jazz relies on a shorthand system of chord notation, which is not universal, not standard, and not terribly logical or consistent, at least at first sight.

This article is intended as a brief general guide for people who are new to this quixotic system and aims to give you a grounding in what any given chord symbol is trying to tell you. I’ve also tried to clear up what I see as the most confusing ambiguities in the way chord symbols are written. Hopefully, I’ve clarified more than I’ve confused!

In recent years, the international success of various fakebooks has led to a welcome degree of standardisation in the way chord symbols are written – but there’s still a way to go. In fact, it’s doubtful the system will ever become totally standardised – it has the character of a living language in that respect. People often write differently according the way they learned and the way they think. You should be able to read anything by anybody.

This article should also give some insight into the variations you’ll find on bits of manuscript paper and on published lead sheets that are often prepared by people not familiar with jazz harmony. It’s something I wrote years ago which someone recently asked to be put up here. I’m afraid there aren’t any funny pictures – if you can think of a good picture to represent a Lydian Dominant chord please feel free to suggest it…

1. TONIC MAJOR CHORDS

The most commonly used symbols for a major chord are:

C, C, C7, C6, C69, CM, CM6, CM7, C9, CM9, Cma,(6) (7) (9)

Typical use is as the I chord in a II-V-I progression. These different chord variations all perform the same function and are used largely interchangeably. Let’s begin by pinning down what is meant by each symbol if they are being used with total precision as per the symbols:

C        Major triad: CEG
C6, CM6, Cma6      Major triad plus 6th: CEGA
C(7), CM(7), Cma(7)      Major 7th chord: CEGB
C9, CM9 Cma9      Major 7th plus 9th: CEGBD
C69        Major triad plus 6th and 9th: CEGAD

(Note that the “”, “M” or “ma” needs to be present for a major 9th chord. If you see “C9”, it means a dominant 7th chord with an added 9th. See below.)

Notice that, if played exactly, these give different flavours of major sound. The triad is straightforward, the added 6th acts as an adornment to the triad, the major 7th chord (with or without the 9th) has a modern open sound and the 6/9 combination has a similar, but slightly smoother modern open sound.

One of the key concepts to bear in mind when deciphering chord symbols is that of context – the style and period of the composition or interpretation being played. Here are some horrendous generalisations (but then, as someone once said, you can’t have a good argument without generalisations).

Dixieland, trad and strict-tempo dance music, as well as much of pop and country music tends to focus on the sound of the pure triad – although the 6th may be added occasionally. The same is true of classically influenced popular dance music such as French chanson and java, tango and the music of Kurt Weill.

Swing, early bebop and much traditional music from Central and South America and the Caribbean tends to focus on the sound of the triad plus 6th. Certain early bebop pioneers also sometimes experimented with the sound of the major 7th.

Late bebop, hard bop, modal, cool, modern Latin music and most of what you could loosely refer to as contemporary jazz tends to use the major 7th (with or without the 9th) or 6/9 combination interchangeably.

Postbop styles such as fusion and country- and folk-influenced jazz will often contain sections where the improviser is expected to improvise predominantly within the sound of various triads.

So, for instance, a “” symbol really has no business being in a Hot Five or a traditional calypso chart – the particular chord sound called for by that symbol is stylistically inappropriate. If you come across one in this sort of context, it’s worth checking with the person who wrote the chart that that’s really what they meant.

In later jazz and Latin charts, you will often see the simple symbol C or C6. This is just shorthand – the generally idiomatic sound expected is C or C69 – you are expected to do more than just slavishly obey the written symbol. The C (with or without the 9th) or C69 sounds are used interchangeably, but they are subtly different. It’s up to you to choose which to play at any given point.

When you see C (most common) or C69 actually specified on the chart, you generally have free rein to play either chord sound. However, some arrangers are very specific when they write chord symbols and it might be polite to play the exact chord sound indicated. In particular, chord charts written for big bands tend to indicate chord extensions with a greater degree of detail than small-band lead sheets. If in doubt, it never hurts to ask.

ALTERATIONS TO MAJOR

The two commonly played alterations to a major chord are Lydian and Lydian Augmented.

a) LYDIAN

C+4 also written C+4, CM+4, CM#4 , Cma+4, Cma#4, (sometimes C+11, CM+11, C#11, CM#11, and you’ll also see b5s instead of #4s or#11s)

This chord symbol means some kind of major chord with an added sharp 4th (you wouldn’t generally play a perfect 4th on a major chord as it’s dissonant against the 3rd). You are free to add the #4th to a 6th, major 7th (9) or 6/9 combination, but note that often to avoid congestion the #4th replaces the perfect 5th in the voicing.

Note also that by convention the “+” symbol means ”sharp”, not “add”. Where you are required to add a tone to a chord you’ll usually see the word “add”.

This is a relatively modern chord sound – appearing from early bebop onwards. While you can often raise the 4th on any major chord, the Lydian is most often used on a IV chord, for instance when the harmony is a II-V-I-IV progression. A chart may read:

Dm7 G7 C F

In these situations you can play the F chord as F+4, even, as here, when it isn’t specifically called for on the chart. This makes sense, if you think about it, since F is the Lydian mode of the home key, C.

A common use of Lydian major is as a substitute for the final I in a chart – as in II-V-bII+4:
Dm7 G7 Db+4

This may look odd if you’ve never come across it before, but you’ll recognise it instantly when you hear it.

In more modern modal and postbop charts, the Lydian chord often appears when chords aren’t progressing around the cycle of Vs. In these contexts it will usually be specifically called for on the chart.

The Lydian chord is sometimes notated by a slash chord (a triad over a bass note):
D/C = D7 inverted or C+4 (strictly speaking, C major 9th, #11th and 13th but no 3rd – see why slash chords are sometimes easier to write and read?)

b) LYDIAN AUGMENTED

C+5 also written C#5, CM+5, CM#5, Cma+5, Cma#5, occasionally C+5

This chord symbol is shorthand. When the 5th is raised on a major chord, it is taken as read that the 4th has already been raised. Again the “+” symbol means “sharp”, not “add”.

So this chord symbol means some kind of major chord with an added sharp 4th and sharp 5th. Well, that’s strictly true, but in practice, this chord type often sounds strongest with just the #5th. Also, to avoid congestion in the voicing, the major 7th tends to be played more frequently than the 6th or 6/9 combination.

A very modern chord type this – 1960s jazz onwards. Its function is sort of as a tonic chord on steroids, as it were – a chord that isn’t so much at rest as sprawled on the floor. So stark is this sound that it is often out of place in straightforward II-V-I situations, except as a final I at the end of a chart:
Dm7 G7 C+5

It is also found in modern charts where chords are not progressing by the cycle of Vs.

The Lydian Augmented chord is sometimes notated by a slash chord (a triad over a bass note):
E/C = C+5

2. TONIC MINOR CHORDS

The logic with tonic minor chords is pretty similar to what we saw with tonic major chords – the only difference between the two chord types being the minor 3rd. The most commonly used symbols for a minor chord are:

Cm, C, Cm6, Cm69, Cmi, Cmi6, Cmi69, CmM, C9, CmM9, C-, C-6

Typical use is as the I chord in a minor II-V-I progression. As before, let’s pin down what is meant by each symbol if they are being used with total precision:

Cm, Cmi      Minor triad: CEbG
Cm6, Cmi6      Minor triad plus 6th: CEbGA
C or CmM      Minor-major 7th chord: CEbGB
C9 or CmM9      Minor-major 7th plus 9th: CEbGBD
Cm69, Cmi69      Minor triad plus 6th and 9th: CEbGAD

(Note that the “” or “mM” has to be in the symbol for a tonic minor 9th. “Cm9” means a minor 7th chord with an added 9th.)

As before, if played exactly, these give different flavours of minor sound. The triad is straightforward, the added 6th acts as an adornment to the triad, the minor-major 7th chord (with or without the 9th) has a modern open sound and the m6/9 combination has a similar, but slightly smoother modern open sound.

Tonic minor chords have the same stylistic and period associations as major chords.

Dixieland, trad and strict-tempo dance music, as well as much of pop and country music tends to focus on the sound of the pure minor triad – although the 6th may be added occasionally.

Swing, early bebop and much traditional music from Central and South America and the Caribbean tends to focus on the sound of the minor triad plus 6th. Certain early bebop pioneers also sometimes experimented with the sound of the minor-major. Late bebop, hard bop, modal, cool, modern Latin music and most of what you could loosely refer to as contemporary jazz tends to use the minor-major (9) or m6/9 combination interchangeably.

Postbop styles such as fusion and country and folk-influenced jazz will often contain sections where the improviser is expected to improvise predominantly within the sound of various minor triads.

As before, in later jazz and Latin charts, you will often see the simple symbol Cm or Cm6. You are expected in these styles to play either Cm69 or C (with or without the 9th) – although it might be argued that the Cm69 is preferred in II-V-I situations. And when you see C or Cm69 you usually have the choice between the two.

3. MINOR SEVENTH CHORDS

Dm7, Dm9, Dmi7, Dmi9, D-7, D-9

Typical use is as the II chord in a II-V-I progression. The chord tones are as follows:

Dm7      Minor 7th chord: D F A C
Dm9      Minor 9th chord: D F A C E

The Dm7 chord is more stylistically appropriate up to early bebop, the Dm9 chord belongs more to the late bop sound onwards.

Not too many people bother writing Dm9 in charts these days – most pianists will just play Dm9 when they see Dm7 anyway. But, as always, be aware of context…

In some charts, from bebop onwards, you’ll occasionally see the I chord in a minor II-V-I progression written as a minor 7th. For instance:
D G7b9/G7alt Cm7

This kind of notation could be sloppiness – the person writing the chart may have meant the C minor chord to be a tonic minor. But throughout the bebop period, the minor 7th (Dorian) sound was increasingly used as a sort of bluesy alternative to the tonic minor sound. You can use this sound whenever you want, even when the chord chart specifies a tonic minor.

This is probably why the minor 7th (Dorian) sound was in on the birth of modal jazz – So What is based on two minor 7th scales, and many other modal tunes made use of this chord quality.

In the modal context, the scale is used for long periods of time and the pianist will usually explore the full extent of the chord scale. So on a modal tune it is usual to play around with the possibilities offered by the upper extensions, such as Dm11 and Dm13, even when the written chord is just Dm7:

Dm11      D F A C E G
Dm13      D F A C E G B

Not all of these tones have to be present in the voicing. Note that when you play up to the 13th in thirds like this, you’re playing the entire chord scale.

These upper extension chords are sometimes specifically called for in arrangements.

4. HALF-DIMINISHED

D, Dm7b5, D(#2), Dm7-5

The half-diminished chord can be seen as an alteration to the minor 7th chord and is typically used as the II chord in a minor II-V-I progression.

The chord tones are as follows:

D or Dm7b5      Minor 7th flat 5th chord: D F Ab C
D(#2)      Optional alteration of natural 2nd: D E F Ab C

The chord symbol Dm7b5 gives a shorthand indication of what’s going on: actually on a half-diminished chord scale both the 5th and 6th are flatted.

The mode implied on half-diminished is Locrian – which would include a b2nd. However, this tone is dissonant against the root. So, if the 2nd is played at all it is usually raised a half-step. The D(#2) symbol is rarely used, but if you see it the composer specifically wants this sound.

Broadly speaking, in pre-bebop style you’d tend to avoid the 2nd in a half-diminished voicing. In more modern styles you are free to add the #2nd if you wish, even when the chord symbol is a straight D or Dm7b5. The 11th is often fair game too.

The 11th can also be played on a half-diminished chord (particularly to accompany the #2nd), though it’s rarely specifically called for in a chord symbol.

5. DOMINANT

G7, G9, G13

Typically used as the V chord in a II-V-I progression. The chord tones assumed to be present are as follows:

G7      Dominant 7th chord: G B D F
G9      The same plus 9th: G B D F A
G13     The same plus 9th and 13th: G B D F A E

To generalise, the G7 and G9 chords are more stylistically appropriate up to early bebop, the G13 chord belongs more to the late bop sound onwards.

Not too many people bother writing G13 in more modern charts – most pianists will just play G13 when they see G7 anyway.

Remember also that dominant 7th chords function as I chords in a blues (G13 is a popular choice in this context, even when the written chord is a simple G7). This bluesy sound can be imported into standard II-V-Is, where you may see I chords notated as a dominant.

Bebop was all about II-V patterns moving at speed, but in a lot of older bop charts, they didn’t bother including the II chord. Just because a chart reads V-I doesn’t mean you can’t play the full II-V-I. Incidentally, some bop tunes contain measure after measure of II-V, II-V, II-V. You don’t have to follow those chords slavishly either, you can just think “sort of dominant” for the whole chunk.

ALTERATIONS TO DOMINANTS

The dominant chord is the most alterable and most frequently altered chord type. Sometimes specific alterations are called for by specific chord symbols, but jazz musicians don’t wait for permission to freely alter the flavour of dominants whenever they like. When writing charts, some people acknowledge this by not bothering to write in specific alterations. Often, where alterations are specified on the chart, they are necessary to match what’s going on in the melody (although you should always check for clashes – this is the area where people most often stuff up). In this case, most jazz players tend to stick to the written alterations during the melody and use alterations more freely during the solos.

a) SUS DOMINANT

Gsus, G7sus, Gsus7, G9sus, Gsus9, G13sus, Gsus13, Gsus4, G7sus4

Note that the “sus” (meaning “suspended”) in the symbol only ever refers to the 4th, even when “4” doesn’t appear. Chord tones are as follows:

Gsus, G7sus, Gsus7, Gsus4m G7sus4     Dominant chord with added 4th: GBCDF
G9sus, Gsus9      The same with added 9th: GABCDF
G13sus, Gsus13     The same with added 9th and/or 13th: G(A)BCDEF

Often, the sus 4th replaces the 3rd in the voicing. Any of the upper extensions may be specifically called for in the chord symbol, but all are freely used, even when the chord symbol is the simple sus or sus4. You might also sometimes see these chords written as G11.

Sus voicings tend to involve placing the 3rd above the 4th to avoid a dissonant minor 9th interval.

Sus chords are quite a modern phenomenon – from the 1960s onwards, where they often appear in modal tunes. Having said that, a common substitution to play is to compress a II-V into a Vsus, as in:

Dm7 G7 C becomes G7sus C

Sus chords can also be notated by a number of different slash chords (we’ll get to those later):
Dm7/G = G9sus
F/G = G9sus
F/G = G13sus

You’ll occasionally see a chord marked sus2. It’s rather a country/folk/pop sound and it basically means play the triad, but with the 2nd instead of the root.

b) SUS b9 DOMINANT

Gsusb9, G7susb9

Note that the “sus” refers to the 4th, not the b9th. The implied chord tones are either of:

G Ab C D F (root, b9th, 4th, 5th, 7th)
G Ab C E F (root, b9th, 4th, 13th, 7th)

A very modern chord type – mid 1960s onwards. It can suggest Phrygian (the classic Hispanic/Oriental sound) but it’s also used as a substitute for a minor II-V:

D G7b9/G7alt Cm becomes G7susb9 Cm

Different flavours of susb9 are also sometimes rendered as slash chords:
D/G
Fm/G
F/G

c) LYDIAN DOMINANT

D7+11, D7+4, D7#11, D7#4

Used in situations when the dominant chord doesn’t resolve down a fifth or semitone (these are technically referred to as “secondary dominants”). A common example is when the dominant resolves to a minor 7th chord on the II degree of the key, eg:

D7+11 Dm7 G7 C

The chord tones are:

D F# G# A C (root, 3rd, #11th, 5th, 7th)

Often the #11th takes the place of the 5th in the voicing to avoid clutter. It’s also common to add the 9th and/or 13th on this chord type, but you’ll rarely see this specifically called for in a chord symbol. Again, some people write b5ths instead of #4ths or #11ths.

d) ALTERED DOMINANT

G7alt, Galt7, G7#9, G7+9, G+7

Typical use is as the V chord in a minor II-V-I progression or as the VI chord in a major II-V-I-VI.

This chord type implies the following scale (the VII mode of melodic minor):
G Ab A# B C# D# F

from which the chord tones are freely chosen. Common choices of chord tones are:
G B F A# (root, 3rd, 7th, #9th)
G B D# F A# (root, 3rd, #5th, 7th, #9th)

This chord type is also freely used to embellish any dominant. You hear it a lot in players such as John Coltrane.

e) 7b9 DOMINANT

G7b9, G7b9+11, G7b9#11

Typical use is as the V chord in a minor II-V-I progression or the VI chord in a major II-V-I-VI.

This chord type also implies an entire scale (the symmetrical eight-note half-step whole-step diminished scale):
G Ab  A# B C# D E F

from which the chord tones are freely chosen. Two popular sets of chord tones are:
F Ab B D (7th, b9th, 3rd, 5th)
F Ab B E (7th, b9th, 3rd, 13th)

Note that the first voicing given above for an alt chord (G B F A#) will also work over a 7b9 chord. These two chord types – alt and 7b9 – are used for different flavours over minor II-V-I and major II-V-I-VI progressions.

This chord type is also freely used to embellish any dominant. You hear it a lot in players such as Charlie Parker.

f) WHOLE-TONE DOMINANT

G7+5, G7#5, G7+

Used interchangeable with the altered dominant chord. This chord type also implies a complete scale (the symmetrical six-note whole-tone scale):
G A B C# D# F

The chord tones usually played are G B D# F (root, 3rd, #5th, 7th).

Incidentally, some people like to write out their dominant alterations very precisely indeed, eg something like G7b9#11 13. Mostly, these will be partial spellings of the dominant chord-scale options we’ve covered.

6. DIMINISHED CHORDS

Bo, Bo7, Bdim

Typical use is as a substitute for 7b9 chords to allow the bass to move chromatically:
Bo C = G7b9/B C

Actually, this is a case of getting the cart before the horse. The diminished chord was used in older ragtime, jazz and blues styles as well as 1930s show tunes – the notion of 7b9 chords came later. There are plenty of examples of genuine diminished motion in blues and older tunes, such as:
C C/E F F#o G/C
Em7 Eo Dm7 G7 C
Bb7 Eo Eb7

The same voicings are generally used for diminished chords as for the related 7b9 chords (although there are other voicings used).

One diminished scale serves four 7b9 chords and four diminished chords. The scale is made up of the roots of all of them in sequential order. For example, the G half-step whole-step scale serves the following chords:
G7b9, Abo, A#7b9, Bo, C#7b9, Do, E7b9, Fo

7. SLASH CHORDS AND POLYCHORDS

We’ve come across a couple of examples of “slash” chords already, but let’s go into a bit more detail.

Slash chords are a chord over a bass note, and are written with an oblique slash. Sometimes the chord on top is a simple triad, sometimes a fuller chord type:
E/C Bb/C

Polychords are an extension of the same logic – a chord over another chord. They are written with a horizontal slash:
C   Eb13
D    Db

A good rule of thumb for pianists is that when you see either of these hybrid chord symbols, you play the simplest possible voicing for each element to give the combination intended – although you’re usually free to play around with inversions.

People write slash and polychords into charts for a number of different reasons.

  1. To indicate pedal point – the classic eg is Miles’ arrangement of Green Dolphin Street – EbM GbM/Eb FM/Eb E/Eb EbM.
  2. Simple shorthand – the chord is another way of writing a standard chord type. For most people E/C is easier to read and play than C9+5. Db/C implies that the composer or arranger wants a specific inversion of Db, with the major 7th on the bottom. E/F implies that the composer or arranger wants a specific diminished-scale voicing (to go with G7b9, Bb7b9, Db7b9 or E7b9, for instance). Sometimes they just indicate a moving bassline. In pop charts particularly, you’ll find things like Fm/D (which a jazz player will instantly recognise as D half-diminished) and F/G (which the jazzer knows as a kind of G sus chord).

  3. The composer or arranger wants a specific voicing, which they can express more cleanly by slash or polychords than traditional notation. Often in the modern context, a series of slash and polychords will be used in combination to notate a harmonic progression that doesn’t make much (or any) sense when analysed as traditional harmony, but relies on parallelism or polytonality for its effect.

  4. The composer wants you to think in terms of hybrid chord scales when improvising. The commonly used substitute for a final C, B/C, implies that you should combine tones from the elements when improvising. B/C is a hell of a lot easier to digest than something like CLyd+9, or C+4+9, or even C7b9. If you see a slash or polychord that doesn’t make sense when analysed traditionally, odds-on you are being instructed to use the two elements to contruct a synthetic non-standard scale or voicing.

Let’s compare what you might play over:

B/C and B
             C

The first (slash) chord is instructing you to play a B triad over a C root. So far so good, but this only gives you four tones to go on – most players would look to expand the possibilities in this context. You have lots of choices, but the basic strategies are as follows.

You could think to yourself, okay, I have a B major chord, but I can also play a C. But C doesn’t naturally occur in the B major scale. So you might choose to play a B major scale with the C added to it:
B C C# D# E F# G# A#

Or you might choose to play a B major scale with the nearest tone shifted to C:
B C D# E F# G# A#

Or you could take the view that since there is a C in the bass, this chord should be interpreted as some kind of C chord. The easiest way to reflect this would be to combine the most basic information necessary to express both C and B chords – interweaving notes from the two triads as a scale:
B C D# E F# G

The second (poly) chord is less ambiguous. It’s telling you to play B triad over C triad. So your first choice would be to use the same six-note hybrid scale comprising those six tones.

Slash and polychords are often primarily instructions to the piano/guitar and bass (occasionally the pianist’s chart will contain a slash chord to dictate a precise voicing and the bassist’s chart will contain a different root altogether). Having said that, a solo instrument may choose to play in the sound of the voicing indicated. But look out for non-traditional sounds notated this way, when you are expected to construct a synthetic scale from the elements given.

8. A WORD ON POPULAR TUNES

Don’t overcomplicate. Popular harmony has a beauty all of its own, so it might not be appropriate to jazz it up with your fancy flat 19ths and sharp 112ths… Sometimes all you need is a beautiful triad. Sometimes even less – which reminds me… You’ll occasionally see a chord marked something like C5. This is the famous guitar “power chord”. Root and 5th – that’s it.

9. IN A SIMILAR SPIRIT…

Always be aware of context. For instance, you wouldn’t use nearly as much harmonic latitude in a big band (where there’ll be anything up to 13 horns playing a painstakingly composed arrangement) as you would in a small-group setting. In addition, it’s usual to stick close to the “pure” harmony during the head and then push the boat out during the solos. As always, listen to the soloist.

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Posted in a) Soloing Scales & Modes, b) Harmony & Comping
4 comments on “Deciphering Jazz Chord Symbols
  1. anentropic says:

    unicode problems :(

  2. Adam Cole says:

    Of course you should have included a picture of Lydia the Tatooed Lady.

    • Jason says:

      Ah yes, you can learn a lot from Lydia…
      Good 4th from the Patriots I see. Incidentally, I gather they once sent Lois Lane to cover the Superbowl, but they put glasses on it so she thought it was an ordinary bowl.

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