Music Theory/Complete List of Chord Patterns

A Major scale has 7 different notes and then ends back on 1, making a total of 8 notes. Each note in the scale is called a scale degree. Each scale degree represents a potential chord. The scale degrees are numbered with Roman numerals so that you can use upper and lower case letters. Upper case represents a Major chord, lower case are minor chords, and lower case with a little circle in the upper righthand corner of the Roman numeral is diminished. In western music chords are traditionally built by using every other note beginning on each scale degree - giving you a choice of 7 diatonic chords in a Major scale.

The formula to make a Major scale is the same for every single Major key. The I, IV, and V are the only major chords in a traditional major scale. The remaining chords are minor with the exception of the 7th which is diminished. The scale numbers would look like this I ii iii IV V (the 5th should have lines above to show its Major) vi vii(o) I. For example in the key of C the scale would be CDEFGABC. Since triad chords are built by using every other note from the one you begin on - a C Major chord would be CEG. The 1st note (in this case C) is called the root, after that you count steps away, starting with C - making the 3rd E. G is then 5 steps away from the root (C) making it the 5th. You can keep extending chords making 6th, 7th, 9th, 11th, 13th chords, and sus4 chords. Since every Major scale has the same formula this can make transposition fairly easy because if you recognize a piece of music is playing a I chord or any other degree of chord from your original key to transpose all you would need to play is the same chord degree in the new key you desire. You also need to know that you can raise and lower notes if desired in the chords you’re writing. If you see a C7#9 it means you raise the 9th a half step.

This is one of the chord trees that will aid in the writing and analysis of music. You can move down the tree but you may not retrograde (go backwards) until reaching the bottom. There are, of course exceptions including cadencing using the IV to I which is called the Amen cadence because of its use in older church hymns. At the end of a hymn people would sing Amen from the IV to I. A good example of a song that uses an amen cadence is ”Let it be” by the Beatles (Amen means let it be!). Moving from a V to vi chord is called a deceptive cadence because traditional western music is usually a battle between the Major V and Major I. You may think of the I of a scale (also called the tonic) as home and the V (also known as the dominant chord) as the car that drives you back home. All chords that have a number immediately after the letter are actually dominant chords with added notes. Dominant chords contain a major triad with a minor 7th. If they are not dominant they will say something like G Maj7 which has a dreamy feel but in the key of C - G is dominant so its notated G7. A G9, G11,or G13 all can be used as a dominant chord. All dominant chords must contain a seventh, though it is possible to leave out the 5th from extended chords such as 13th chords. The I chord is your musical home but you may go other places during your journey but you usually drive back home using the V (the car of the key) to get there. If you end your phrase or piece using V to a vi chord this is also (see above) called a deceptive cadence (or ending. This is because the Major 5th makes you feel like you are going home to your happy home the I chord but instead you land on a minor chord which will sound sad but still complete.

You may move across the degrees and interchange the chords or can skip degrees entirely if so desired but here is a nice chord progression: Example- I, IV, ii, V, I, vi, ii, V, I) A good key to practice it in would be C because there are no sharps or flats to remember but you can do it in ANY major key. In C this Progression would be C Maj, F Maj, D minor, G major, C Maj, A minor, D minor, G Major, and back home to C Maj.

I IV  ii  V  I  vi  ii  V  I

In the key of C
 * I: C Maj
 * vi - iii: A minor to E minor
 * IV - ii: F Major to D minor
 * V - vii°: (vii° the little circle at the end means diminished) these chords can also be notated as G Major to Bmin♭5 (Minor flat 5 chords are the jazz notation for diminished)

Note numbers in parentheses are optional:

Dominant/Seventh
Normal

The dominant seventh is sometimes just called the "seventh", even though it contains a minor seventh and not a major seventh.

Altered

Suspended

Any chord with a major third can have the third replaced by a major second or perfect fourth to form a suspended chord. Given a chord C, this would be written Csus2 ("C suspended second") and Csus4 ("C suspended fourth") for a major chord. As these only apply to the major second and perfect fourth, there is no such thing as, say, a Csus6, which would probably be properly written as Gsus4/C or C5add6 if it has a fifth, or else Am/C. However, in certain circles it is thought that replacing the fifth in a triad with a sixth is a type of suspension, eg Csus6 would contain C, E and A, rather like an Am. This is however more accurately notated as C6.

Minor
Normal

Diminished

Notice the diminished seventh chord has a double-flatted seventh, which is enharmonically the same as a sixth, so you may find the diminished chord alternately written as "1 ♭3 ♭5 6". The double-flat notation is more correct because it shows how the seventh is further diminished from the half-diminished state.

Sometimes a diminished seventh chord is notated the same way as a diminished triad. Even more confusingly, sometimes both forms are called the "diminished chord"! You can make the distinction between the two to avoid ambiguity. However, keep in mind that they're ultimately very similar chords anyways, and you can usually interchange them.

Other
It's worth mentioning that you might hear some individuals (usually rock guitarists) call fifth chords 'power chords'.

9th, 11th, and 13th chords
7th chords can be extended to 9th, 11th and 13th chords. If you have a C7 (C dominant seventh), then the corresponding chords would be C9, C11 and C13. The C9 is a C7 with a major ninth (or second) added. The C11 is a C7 with an eleventh (or perfect fourth) added as well as the major ninth. The C13 is a C7 with a major thirteenth (or sixth) added as well as the major eleventh and major ninth added.

The same principles that can be applied to seventh chords apply to minor and major 7th chords. For instance, you can have a minor 13th: 1 ♭3 (5) ♭7 9 11 13. The notes added are always the same: ninth, eleventh, and/or thirteenth, not augmented or diminished. Only the seventh chord base changes.

It is very uncommon to extend a major 7th chord with an 11th. This is because there would be an interval of a minor ninth between the third and the eleventh. If an eleventh is played, it is usually altered (this is dealt with below).

Additions
When a note is added to these chords in a manner that does not fit the tables above, it is often written "addX", where X is the number of the added note, e.g., add6 for an added sixth. For instance, C major with an added sixth would usually be written Cadd6. If the number is above 7, then it will be an octave higher than the root note.

Do not confuse Csus2 and Cadd2, or Csus4 and Cadd4. Suspended chords must not have a major third, but major chords with additions must. (Note that in jazz, suspended chords sometimes have a major third added, but only when the player wants dissonance).

Do not confuse Cadd9 with C9; the latter has a minor seventh, but the former does not.

An "added second" and "added ninth" are often considered synonymous, because a ninth is a second. Some musicians argue they imply different voicings of the chords, for instance, add9 should have the second raised an octave, but add2 should not. The "added ninth" is more common, especially since it is rare that one wants to add a major second that is literally one whole tone away from the first (and possibly a third as well).

The 9th here is what is often referred to as a compound interval, that being an interval greater than an octave, such as a 9th being an octave up from a 2nd, a minor 10th being an octave up from a minor 3rd... Greater intervals, e.g. a minor 17th, theoretically exist (this being a minor 3rd raised 2 octaves) but such things above a modification of a 13th are never spoken of. To create a compound interval one would add 7 (once for every octave) raised to the number in the name to raise the interval. The same applies subtracting seven to lower the pitch by octaves.

Alterations
Sometimes something such as "♭5" or "♯5" (also written "-5" and "+5", respectively) will be appended to the end of the chord; this means play the chord as normal but flatten or sharpen the fifth respectively. (This is why C&oslash; is sometimes written Cm7♭5, because a minor 7th with a flatted fifth has the same notes as a half-diminished chord. Similarly, it may also be pronounced "C minor seventh flat five".)

Any of the extension notes (9th, 11th and 13th) can also be altered, something fairly common in jazz. The possible alterations are ♭9, ♯9, ♯11 and ♭13. You may be wondering why there is no ♭11 or ♯13. Stop and think for a second about which notes they would be in the key of C major. The ♭11 would be E, which is the major third in C, and the ♯13 would be B♭, the minor 7th, so a chord symbol like C ♭11 ♯13 would imply C7. Which would you rather read?

The table below shows common altered chords:

The names in brackets after the full name refer to the mode from which the chord is derived (there should be a section on this eventually).

Bass notes
The bass note of a chord is the lowest note of the chord. The most common case is that the bass note is the root note, for instance, in a C major chord C-E-G ascending in pitch from left to right, the bass note is C, which is the root note. But if the chord were instead G-C-E, it is still a C major chord (specifically, an inverted C major), but G is the bass note, while C is still the root note. Sometimes the bass note is omitted for brevity when it is still a part of the chord, which may be needed, for instance, when many rapid chord changes would otherwise make the names illegible on a printed score.

Occasionally, bass notes are not a part of the original chord. For instance, a D minor does not have a C note, but sometimes Dm/C is seen, meaning the D minor chord is played normally but with a C note below it. These are often called slash chords.

This notation can also indicate a polychord.

Polychords
Polychords are superimposed chords. They are more common in some kinds of music (jazz) than others (classical).

This may occur, for instance, when a piano player plays a D minor with the left hand (possibly omitting its fifth) and a G major with the right hand. The most common notation for a polychord is $upper chord⁄lower chord$, for example: $G⁄Dm$ (D–F–A—G–B–D). In case a very specific voicing is needed, the individual chords can be written in their desired inversions, for example: $E♭m/G♭⁄Cdrop2$ (C–G–E—G♭–B♭–E♭).

A common use of polychords is arpeggiating one chord against a different chord. For instance, on a piano, the left hand may be holding down a G5 chord while the right hand arpeggiates D minor chords. This would be notated Dm/G.

Polychords might be used as exotic voicings for many chords. The following examples use a pipe (|) to separate the upper chord from the lower one. (the examples are given here for a C chord)

Quartal chords
Some arrangements use chords based on fourths, often two fourths in the upper notes with an independent bass, which gives the following possibilities:

Of course, the fourths part of the chord can be present in two other inversions - sus4 or sus2, making B♭7sus4/C, Ebsus4/C and Absus2/C equivalent for instance.

Chord implication
Sometimes chords are not specifically indicated by notes, but are indicated by the chord structure, or even notes that don't form chords by themselves but sound like they belong to a certain chord. The most usual way to handle this is to put the chord name in parentheses. Implied chords are also often used when there are constant chord changes throughout a section (several per measure), and marking each one would make little sense, so the "underlying" chord is chosen (usually a chord the others are temporarily centered around). Sometimes sheet music will use only implied chords, in which case often chord names will appear normally, and perhaps a footnote will state something such as "chords reflect implied harmony".