2. Background

Popular chord notation systems in use today describe the pitches of the component tones of most chords relatively to a reference major scale starting at the chord root. For example, the symbol

Ab6(9)(#11)

usually means “take the root triad from the Ab major scale, add the scale’s  6^th , 9^th and 11^th degrees, then increase the pitch of the 11^th by a halftone”.

Simple as it seems, virtually all current notation systems lack rigorous syntaxes and consequently suffer of one or more serious inconsistencies. The most famous of them – and the most terribly confusing for beginners – arises in the conventional notation of dominant chords, in which an unmodified “7” normally refers to the flattened 7^th of the major scale. Quite curiously, the major 7^th takes about a dozen different, sometimes exotic, representations, more or less justified by local usages, nationalities and personal tastes of authors and editors.

Another frequent source of confusion is the treatment of omitted or implicit tones. For example, in some systems, the symbol “C9” simply means adding the major 9^th to the C major triad, while in many others it implies the inclusion of the minor 7^th as well. The reader is rarely warned about the correct interpretation, and in most cases must learn it by trial and error, according to the context.

A big challenge that common chord notations have to face is the trend-off between clarity and conciseness. The chord symbol in the above example is quite explicit and unambiguous, but at the cost of being cumbersome and slow to write, either by hand or by typesetting. In fact, typing and positioning fairly readable chord symbols is typically one of the most time-consuming stages of popular music score editing.

In this article, a new notation system for describing harmony in popular music is presented. It works with special symbols called chordgrams. The example below illustrates how chordgrams represent harmony changes in comparison with typical “fake book” chord symbols:

As regards chords, chordgram notation is free from inconsistencies, compact, easy to learn and fast to read and to write. In several aspects, chordgrams are similar to ordinary notations. First, they  are primarily designed to represent tertian chords (those formed by stacking successive thirds from an underlying scale or mode). Such chords are the most frequently used in popular music, including jazz and other harmonically dense styles, such as 50-70’s Brazilian popular music. Second, they are limited to a representation of the chord in its fundamental position, without imposing an exact distribution of the upper voices. Also, they make use of the major scale as a reference to represent chord tones.

However, chordgrams have some attractive features that make them an appealing auxiliary or alternative notation for ordinary chord symbols:

-         Uniform, fixed-size symbols for all chord types;

-         Fast handwriting;

-         Explicit representation of the chord tones;

-         Language-independent symbols;

-         Easy and fast learning, both for beginners and experienced users of ordinary chord notations.

But chordgrams are not limited to chord notation. As it will be shown later, one surprising side benefit of chordgram notation is its ability to reveal, in a very explicit and natural way, the relationship between the represented chords and their subjacent scales or modes. This makes it a helpful tool for analysis and improvisation. Actually, chordgrams can be used to represent complete scales and modes, in a straightforward way and without loss of clarity and conciseness. 

3. Chordgram Basics

The main idea behind chordgram notation is the positional representation of chord tones. This means that any information about a particular chord tone must be displayed in a unique, well-defined location in the chord symbol printing area. One such location plays the role of a label, to be filled with precise instructions on how to play the corresponding chord tone.

One great advantage of a positional notation is that it dispenses with the use of numbers to distinguish between chord tones. Chord representation can be reduced to a few symbols, suitably distributed among the chord tone labels. These symbols act as modifiers, which behave like accidental marks, but may perform more general tasks.

Chordgrams adopt an optimal positioning convention for tone labels (in a sense that will become clear soon), along with a simple, aesthetically appealing set of modifier symbols. They are both very easy to learn and remember, and are designed to simplify the notation of the most frequently used chords, without becoming cumbersome when dealing with more complex harmonies. The following two sections describe in detail the chordgram positional structure and modifier set.

3.1. Chordgram Positional Structure

The chordgram positional structure can be easily understood by defining a reference major scale, starting at the root of the chord to be notated. The seven degrees of the reference scale are then displayed as follows:

An easy way to remember this particular disposition of the scale degrees is to think of the root (1^st tone) as the “center”, the 2^nd and the 3^rd as “low”, the 4^th and the 5^th as “middle” and the 6^th and the 7^th as “high” scale tones, statements in obvious agreement with common usage.  

The locations of the seven digits are then interpreted as chord tone labels (see above), to be filled with relevant information about the chord tones themselves.

Extended chord tones (9^th , 11^th , 13^th) simply share the labels of their below-octave equivalents:

In the context of popular music, in which octave equivalence is more strongly assumed than in more formal styles, these positioning overlaps don’t lead to any relevant ambiguity.

One nice aspect of this representation is the clear-cut separation between the tetrad tones (3^rd, 5^th and 7^th) and the chord extensions (9^th, 11^th and 13^th), respectively stacked to the right and to the left of the root symbol. It works as a reminder of the very distinct roles these two sets of tones play in popular harmony, therefore making chord identification and analysis both easier and faster.

In a chordgram, the root label (‘1’ in the above figure) is filled with the conventional letter symbol for the chord root (including a sharp or flat, if needed). The remaining tone labels are filled with special symbols that act as modifiers, indicating the tones to be played and their individual departures from the reference major scale. The following sections give a complete description of the chordgram modifier set.  

3.2. Basic Tone Modifiers

There are four modifiers which are more often employed than any other in chordgrams. They are the blank (   ), the dot ( • ), the plus   ( + ), and the minus   ( - ) modifiers. Here is how they work:

The blank (   ) modifier

            A tone whose label contains a blank modifier (i.e., is left unfilled) is meant to be avoided when playing the chord. In a first approach, this can be safely interpreted as “don’t play this tone”. The meaning of avoided tones will be refined later, when they will be distinguished from omitted tones.

The dot ( • ) modifier

            Placing a dot in a chord tone label tells the reader to play that tone unaltered, i.e., with the same pitch it holds in the reference major scale.

The plus ( + ) modifier

            Placing a plus sign in a chord tone label tells the reader to play that tone one halftone above its pitch in the reference major scale.

The minus ( - ) modifier

            Placing a minus sign in a chord tone label tells the reader to play that tone one halftone below its pitch in the reference major scale.

Actually, the dot, plus and minus modifiers work exactly the same way as relative natural, sharp and flat traditional accidental marks, respectively. Indeed, one could reasonably ask why these widely known symbols shouldn’t be used instead.

There are at least four good reasons for it. First, chordgram modifiers take fewer pencil strokes to be drawn, and this considerably speeds handwriting. Second, they produce objectively cleaner chord symbols, making chord recognition easier and faster. Third, they eliminate the risk of misinterpreting root-symbol sharps and flats as modifiers. Fourth, as put above, they have only relative meanings, while sharps and flats take absolute meanings in other contexts (such as in key signatures or in the piano keyboard), therefore becoming a potential source of mistakes, especially for beginners.

For these reasons, traditional accidental marks in chordgrams appear only as root modifiers. In fact, the root is the only chord tone in a chordgram that is represented like in ordinary notations.

“My-first-chordgram” example

As a very basic example, here is a step-by-step recipe for writing the B flat major triad chordgram:

1. write down the root letter symbol and accident:

2. add a dot label for the 3^rd , to indicate that it’s major, i.e., unaltered with respect to the major scale:

3. add a dot label for the 5^th , to indicate that it’s perfect, i.e., unaltered with respect to the major scale: 

4. leave the remaining labels blank, as their corresponding tones aren’t meant to be played.

Incidentally, triads are among the very few chord types for which the chordgram representation requires more symbols than ordinary notation.

3.3. Chordgram Completion for Analysis and Improvisation

Determining the missing tones of a chord in order to reconstruct its generating scale is the object of chordscale analysis. Understanding chordscales is a necessary step in mastering melodic improvisation, which is an essential feature of several prominent popular styles, such as Jazz, Bossa Nova, Rock, and many Latin genres.

A careful chordscale analysis typically requires transcribing the tones from the chord symbol to a regular staff, then filling the gaps between tones and adjusting accidents, according to the melodic context and the stylistic preferences. For example, if the chord has a major 3^rd , Jazz improvisers generally assume that the scale contains an augmented 4^th , while Rock musicians tend to favor the perfect 4^th , used mainly as a passing tone. 

It turns out that chordgram notation is a natural born tool for chordscale analysis. With chordgrams, the analysis can be made “in place”, without the need of an auxiliary staff, because the inference of the missing chord tones can be graphically attained, by filling the chordgram blank labels. Such operation is denominated chordgram completion.

In principle, chordgram completion can be performed by the musicians on their own parts, during the rehearsals or even at the backstage, minutes before a live concert. Since chordgrams are practically fixed-size symbols, no extra space is needed in the sheet for the analysis.

After completion, a chordgram becomes an extremely compact – but also clear and explicit – representation of a scale. With some training, it is possible to play the scale by reading it directly in the chordgram – a very powerful tool for improvisation practice.