Chord Scale Harmony

Chord scale harmony refers to the collection of chords that pertain within a scale. As we will see below the harmonic structure can be built on top of each scale degree. Scale degrees makes an easier approach to apply to any key as they are identified as roman numerals.

Chord Tones

When refering to chords, we typically label the notes within a chord as chord tones. Therefore we can define a chord as a collection of chord tones. Scale degrees on the other hand are the notes within a scale, derived from a key centre, in which chords are built upon.

Major Scale Chord Formula

The fundamental scale in western music is the Major Scale (Ionian Mode) and concepts such as chords and scales are typically derived from this scale.

When refering to chords we can implore a roman numeral numbering system. Using a number system is an easier approach for transposing to different keys.

Major Scale Harmony Formula

I

ii

iii

IV

V

vi

viidim

What does this tell us? The scale degree which the chord is built upon and the tonality of each chord. We can identify the major chords via the capitalised numerals and the minor & diminished chords being the lower case numerals.

Scale Degree	Tonality	Roman Numeral
1	Major	I
2	minor	ii
3	minor	iii
4	Major	IV
5	Major	V
6	minor	vi
7	diminished	viidim

Applying the Formula

Now if we apply the above harmonic formula to the key of C, we can then identify the chords within C major:

C Major Scale Harmony:

C

Dm

Em

F

G

Am

Ddim

I

ii

iii

IV

V

vi

viidim

This harmonic major scale formula can be applied to any of the 12 keys in music. By knowing this information we can identify the key of songs in Major keys and is also the first step towards understanding chordal harmony in modes.

Applying this to Chord Progressions

The following chord progressions are to be practiced in all keys.

Major Chords I, IV & V

As seen in the formula above, the Major Scale Harmony contains three major chords I, IV and IV. Becoming familiar with these major chords will help you quickly identify the key of songs in Major keys.

. .

I

IV

V

I

. .

C Major - I, IV & V

. .

C

F

G

C

. .

Tips to help you identify a song's key

• Look out for the two major chords a tone apart ie. the IV & V chords. This leaves the I chord to be the key’s identifier
• Rather than the first chord, the last chord of a song is a better indicator of a song’s key.

Turn around Progression

. .

I

vi

ii

V

. .

Progression Cycled in seconds

. .

I

ii

iii

IV

V

vi

viidim

I

. .

Progression Cycled in fourths

. .

vi

ii

V

I

IV

viidim

iii

. .