What is a Chord?

A Chord is a "set of notes" usually played simultaneously. A Chord describes a whole "set of notes" and not any individual notes.

Every Chord has a distinct sound and mood. Chords are the harmony of a song. While we identify "melody" by the sequence of notes played, we identify "harmony" by the interaction of the Chords. Chords are the foundations of a song.

We use the word "Chord" to distinguish it from a "Scale" (please see document entitled "Scales"). A "C Major" chord is completely different from the "C Major" scale. Whereas a song may be played in a specific Scale, the Chords to a song will change as the song progresses. This is called a chord progression.

Chord Root

Every Chord has a Root by which we name the chord. The Root is the base of the Chord or you may think of it as the "bass" of the chord (The way in which you hear the basis of a chord and the "bass" is very similar).

For example, for a song in the scale of C Major, the chord progression could be C Major, A minor, F Major and G Major. In this case, the Roots of the chords are "C", "A", "F" and "G" (a likely progression for the bass-line too).

Intervals

An interval is the "distance" between notes (in a chord). Let's start off with diads (ie two notes played simultaneously -or- 2 note chord). You can describe the "distance" in terms of semitones or by its name.

Let's start off by looking at how the intervals are named (Bear in mind that we are talking about two notes played together). The classical music academics named the intervals by the quality of sound produced. If the sound was smooth and pleasant, it was called consonance: If it was strained and unpleasant, it was called dissonance. From this subjective "quality assessment", the names were derived.

You will notice that each interval is numbered (ie 2nd, 3rd, 4th, 5th, 6th and 7th). The numbering comes about by "counting" the "letters" (eg. C to D is 2; C to E is 3; C to F is 4; C to G is 5; C to A is 6; and, C to B is 7). The numbering disregards whether the note is sharp or flat.

The intervals with the most consonance are Unison (playing the same note twice) and Octave. They only involve the root. Let's look at more!

The main intervals are the Perfect 4th (5 semitones apart), Perfect 5th (7 semitones) and the Dominant 7th (10 semitones). They have special names because they have much consonance.

What's the big deal? Why do they sound pleasant? It's actually because of the relative pitches (frequencies) of the notes. Let's say the Root is "C", and let's play a diad using "C" and "G". The pitch of "G" = "C" x 3 / 2 (ie for every 2 oscillations of "C", there are 3 oscillations of "G"). When played together, there is a smooth "ringing" caused by this mathematical relationship which is pleasant. Hence the name "Perfect" 5th.

Perhaps not surprisingly, the note "F" = "C" x 4 / 3 (appx), hence, called the Perfect 4th. Again, the note "Bb" is approximately "C" x 7 / 4, and called the Dominant 7th.

Having set the 4th, 5th and 7th, the next best consonance happens to coincide with the Major Scale and hence were named Maj 2nd (C to D), Maj 3rd (C to E), and, Maj 6th (C to A). Note that "C" to "B" is actually dissonant but, for completeness, the interval is called the Maj 7th.

Having set the 2nd, 3rd, 4th, 5th, 6th, 7th and Maj 7th, the leftover intervals (which happen to be flat notes) were conveniently named min 2nd (C to Db), min 3rd (C to Eb), and, min 6th (C to Ab). It doesn't help that this has little to do with the minor scale.

The only remaining interval is C to Gb/F# and this is named as the diminished 5th (for C to Gb) or augmented 4th (C to F#). When referring to a Note, the word "diminished" means "flattened" and the word "augmented" means "sharpened".

It is important to note that it the words "Perfect", "Dominant" and "Major" are usually dropped. If you were to only use the Major scale to name the intervals, you would be mostly correct BUT except for the Major 7th. Hence, you never drop the word "Major" for the Major 7th.

The last column introduces another method of "declaring" chords. Here the notes are numbered using the Major scale and all other notes are considered either "flat" or "sharp". This system declares the notes involved separated by commas. So a 5th interval would be "R, 5" and the Dominant 7th interval would be "R, b7". This system is never ambiguous and extremely accurate because every note is declared (and the rules are fixed). However, these are not really chord "names" per se.

SideNote - Guitarists like to play a 5th interval plus an octave root (ie root, 5th, octave) and refer to this as the "power chord". It's actually a 5th chord.

Basic Chords

Having looked at the diad (2 note chord) intervals, let us now look at the triads (3 note chords).

The triad is based on the Root, 3rd and 5th of a scale.

Note - The augmented scale (aka whole tone scale) is a 6 note scale where every note is separated by a whole-tone (ie 2 semitones). The diminished scale is an 8 note scale where the separation alternates between whole-tone and semi-tone.

In addition there are also "replacement" to chord notes. These are the suspended 4ths and 2nds. They are suspended because they cannot be classified as Major or minor chords. In a suspended 4th, basically the 4th "replaces" the 3rd (the same applies to the suspended 2nd).

The next set of basic chords are the 7ths. These are 4-note chords made up by adding a 7th (whether diminished, dominant or augmented) to the triad.

At this point, to avoid any confusion, it is important to DROP the word "Major" from the chord-name when describing a Major triad. You'll see why below.

The last four chords are more complicated because of possible misunderstanding.

Consider the 7th augmented 5th chord- Is it the augmented 5th triad with added 7th? Or is it a 7th chord with an augmented 5th (ie sharpened 5th)? Luckily, interpreting it both ways will give the same chord (ie R,3,#5,b7).

Next, consider the 7th diminished 5th chord - Is it the diminished 5th triad with added 7th? Or is it a 7th chord with a diminished 5th (ie flattened 5th)? The chord structure is R,3,b5,b7 which means it is a 7th with diminished 5th. This is often very confusing.

The obvious question is "What then is the diminished 5th triad with added 7th?". This would be R,b3,b5,b7 and it's called the half-diminished 7th. This too is often confusing.

The last one is the diminished 7th! It is a diminished 5th triad with added diminished 7th. Structurally, it is R,b3,b5,bb7. The origin of this chord is different from the rest because it relates back to the diminished scale. It is a special chord because the spacing between each interval is exactly the same (ie 3 semitones). Note - aka "the diminished chord" aka "dim7" aka "dim".

Looking at the last four sevenths, confusion arises because of the ambiguity of the words "diminished" and "augmented". It is hard to tell if they refer to the chord or the note.

As such, I would like to introduce you to a chord-naming system which utilises most of the traditional chord names and methods but is very specific when describing chords or notes.

System for Chord Names

IMPORTANT - The chord-naming system from here on is very specific and will mean that some traditional names like 7dim5 and half-dim7 will not be used. However, be assured that, using this system, any named chord will be easily understood by musicians.

The system used has the following components:-

The system has a specific order of components (ie Base-Chord, Alteration, Replacement, Additions). The point is to declare components only if needed. If a chord qualifys as say an "aug 5 chord", there is no point in calling it a "major chord" with alteration of a "sharp 5th".

"Priority" is mentioned for most of the components. Priority only comes into play when a component can be named in more than one way. How does it all work? Let's see a few examples with root "C":-

3-Note Chord Listing

The following table is a chord listings for 3-note chords using the chord-naming system described above. This time, guitar chords are also included in root "E" and "A".

The guitar chords are quoted by fret-position in the order of EADGBE strings (0 = open string, x = not played, o = optional). Example: Edim5 is 0120xo meaning the chord is held as open on top E string, 1st fret of A string, 2nd fret on D string, open on G string, not played on B string, and, optional open on bottom E string (ie not absolutely necessary).

Shortened Chord Names

At this point, I would like to introduce a short-cut for the "added 7th" chords as well as the "added 6th" chords (in that order of priority).

Actually, the same rules still apply except that, for 7ths and 6ths, the word "added" is not needed (ie Cmin add7 is now Cmin7). Furthermore, the alterations and replacements are declared after [eg Csus4add7 is now C7sus4, and, Cmin(+5)add7 is now Cmin7(+5)].

So, what becomes of the traditional 7aug5, 7dim5 and half-dim7?

Note - the slash (/) is used as a separator to prevent any misunderstanding. This only applies to the aug and dim base-chords (because the chord-names contain numbers).

4-Note Chords

The following table is a chord listing for 4-note chords. Note that only 7ths and 6ths are using the allowed short-cut names. All other additions have the word "added" declared.

* indicates departure from traditional chord names.

Note - For keyboards - To play a chord uninverted, notes numbered greater that 8 are assumed to be played one octave beyond the root.

Note - For guitars - The chords shown may differ somewhat from the chord-books. The chords shown are the least inverted forms which can be easily played.

Advanced Chord Names

When a chord has many "additions", it is important to be aware of the traditional chord names and how the system (used in this document) can differ from it.

For a base-chord with an added 7th, both traditional names and the system accept the chord-name 7th. Both also accept "added 6ths" as named 6th.

Even for the added 9ths, added 11ths and added 13ths, both traditional names and the system accept that the word "added" or "add" must be declared.

The reasons will be made clearer when you compare the traditional names and this system's names in the table below.

As you can see, the system used here can be somewhat "wordy" and long but is not ambiguous.

For traditional guitar chord-names, the names 9th, 11th and 13th are just those notes added to the 7th chord.

For traditional keyboard chord-names, the names 9th, 11th and 13th imply that the notes preceeding the name are accumulated (eg. 11th chord is 7 add9 add11).

5-Note Chord Listing

The following table is a chord listing for 5-note chords.

* indicates departure from traditional chord names.

Inversions and Equivalents

An inverted chord occurs when a chord is not played as a "straight root" chord. Example: a C major triad uninverted is played as C,E,G (from lowest note to highest note). The first inversion is played as E,G,C and the second inversion is G,C,E.

The same applies to non triads as well. Example: Amin7 ; Straight root chord = A,C,E,G ; 1st inversion = C,E,G,A ; 2nd inversion = E,G,A,C ; 3rd inversion = G,A,C,E.

As it happens Amin7 (A,C,E,G) and C6 (C,E,G,A) are equivalents. When you play Amin7, it is also an inverted C6 (and vice-versa). As with all inversions, the basic difference is the perception of what the root note is.

Using inverted equivalents is very useful especially if the straight root chord is awkward or inconvenient to play.

The table below lists chords and their inverted equivalents. The "transpose" column denotes the root of the equivalent in semitones (from the starting chord). Example: With a starting chord of Amin7, the equivalent C6 is a transpose of "^+3/-9". All this means is that "C" is 3 semitones UP from "A" (or 9 semitones DOWN from "A").

Guitar chord notes within "{" and "}" (curly brackets) denote the root.

For guitars, inversions are a way of life. On guitar, as long as the root is the bass-note and the 3rd and 5th appear later, it is a straight root chord. For additions, as long as they appear last, it is still a straight root chord. Even if an addition appears between the 3rd and 5th, it is considered as a small inversion.

The practical application of equivalents is interesting. Example: You can pass-off any song diatonic to C major (or A minor) by only using Amin7, Dmin7 and Emin7. This is because Amin7 = C6 ; Dmin7 = F6 ; Emin7 = G6 = Bmin(+5)add11 (For more on diatonics, see Chord Reference below). For guitar, I recommend using 575555, x57565 and x79787 respectively.

More Naming Techniques

A "BiTonal Chord" is a chord played over a non-root bass. This is really a matter of perception. For example, if you were playing a Cmajor chord over a bass of "A", then the resultant chord is Amin7 (ie A,C,E,G). We can assume this because the perceived root will be the "A" bass-note.

But what if the song has a static chord over bass progression? Or what if the song has a chord progression over a static bassline? In that instance, it is easier to use the "Chord-over-Bass" description.

Example from above would be written as C/A (ie "Cmajor" over an "A" root/bass). In this way, a chord progression can be described as Amin, Amin/G, Amin/F, Amin/E (which conveys the message far better and easier than standard chord-naming).

Another use for the "Chord-over-Bass" method is where a chord doesn't have a 5th note.

Example: C,D,F,A (R,2,4,6) - Using traditional or the chord-name system, it would be "C6 omit5 sus4 add9" (using "omit" is acceptable) or cheat using C6(--5)sus2 or C(++5)sus4 add9. In Chord-over-Bass, it's just Dmin/C.

Chord Reference (mode diatonic)

It is nearly impossible to list every conceivable chord in every root-key. Instead of repeating the chord listing from part 1 in different keys, I thought that it would be more useful to look at chords which are "mode diatonic".

In a scale, all of its notes are "diatonic" to that scale (ie they conform with that scale). Therefore, if all the notes of a Chord happen to belong to any Scales, then the Chord is "diatonic" to those Scales.

Example: Chord "A minor" comprises A,C,E - so the "A minor" chord is diatonic to the scales of CMaj, Amin, FMaj, Dmin, GMaj and Emin (ie any scale with all those notes).

If it does not conform, then it is "chromatic" to that scale.

Tabled below is a list of of chords which conforms to the C major and A minor scale. In music terminology, they are modal diatonic chords (Major and minor belong to a group called "Modes"; see article on Scales). In other words, all these chords only use the white-notes on a keyboard.

For the guitar chords, I have tried as far as possible to present moveable chords (usually in the main guitar chord column). A moveable chord is a chord which can be transposed by moving the finger position up or down the neck. So to transpose a moveable chord up by one semitone is to move your hand (in the same hand-shape) up to the next fret.

Again for guitar, many moveable chords are "barre-chords" or "bar-chords". This is where the index-finger acts as a "bar" (like a "capo") pressing down on all strings of a fret. Basically you are emulating an open chord (max.= 3 finger chord) where the index-finger represents the open strings and the remaining 3 fingers take up the chord position.