How to Write Slash Chords in Roman Numerals | Correct Way

In music, how to write slash chords in Roman Numerals are used to write chords. Taking it straight, we need to understand slash chords and Roman numerals. Let’s begin by discussing Roman numerals. Minor chords are represented by smaller Roman numerals, while the major chords are represented by capital Roman numerals. As an example of how Roman numerals are used in music, let’s take a straightforward example.

C Major scale: C D E F G A B C

Family chords of C major	C	Dm	Em	F	G	Am	B dim	C
Roman Numerals	I	ii	iii	IV	V	vi	vii0	I

Triad

It is possible to make a chord with three notes. It is called a triad chord. Any major or minor chord has three musical notes to make a chord. C, E, and G are the notes of the C Major chord.

Chord Inversion

An inversion is a variation of a chord based on a triad. To know chord inversion, we must understand the notes of the scale and the chord. First Inversion and Second Inversion depend on triad chords. The lowest note, or the bass note, actually defines inversion.

Example: C Major

Root Position: C-E-G.(bass note is C here)

First Inversion-E-C-G or C/E(E is the bass note on the C Major chord)

Second Inversion-G-C-E or C/G(G is the bass note on the C Major chord)

Another way that we can express the Inversion of a chord:

a-Root position b-First Inversion c-Second Inversion

For the C Major scale, C is the root of the scale. We can denote it as I(Roman numerical)also.

C Major Scale

Root Position: C-E-G or I_a

First Inversion-E-C-G or C/E or I_b

Second Inversion-G-C-E or C/G or I_C

Roman Numerals

In C major scale C, F, and G are the major chords, and D and E are the minor chords. Interestingly, B diminished can partly use alternative as a minor chord because of its contraction. Now we can see capital and smaller Roman numerals according to the chords. In C major scale, C-F-G is in capital numerals, and D-E-B is in smaller Roman numerals.

C-F-G I-IV-V

Dm-Em-B⁰ ii-iii-Vi

Some practical uses of Roman numerals

In music, lots of chord progression can make a song or musical piece.

1. ii-V-I progression means Super tonic, Dominant and Tonic chords will play one after another.

Ex. ii-V-I in normal form

C Major: Dm-G-C. G Major: Am-D-G. A Major: Bm-E-A

2. iii-vi-IV progression means Mediant, Submediant, and subdominant chords will play one after another.

Ex. iii-vi-IV in normal form

C Major: Em-Am-F. G Major: Bm-Em-C. A Major: C#m-E-A

Slash Chords

Slash chords indicate the bass note over the chord. As an example, we take the C Major chord. Commonly any chord made with three musical notes it is called a triad. In C Major chords, 1st,3rd, and 5th notes or C, E, and G are the notes of the chords. Tonic is the bass note of C major. In the Second inversion of the C Major triad, G will be the bass note of the chord. It can write as C/G, which is a slash chord. The third inversion is C/E. E must be the bass note.

slash chord=scale degree/bass-note

Example of slash chord

A/E means A major chord with a bass note of E.

C/G means C major chord with a bass note of G.

Chords in Roman numerals(All major chords)

All the Major chords must write in capital Roman numerals, and all minor chords in small Roman numerals, according to the book “First steps in Music Theory” (ABRSM grade 5). It is essential to keep in mind that all chords work relative to their tonic chord.

Note to remember that

In the root position Tonic is the bass of the chord. (C-E-G)

In first Inversion 3^rd note of the chord must in bass.(E-G-C)

In first Inversion 3^rd note of the chord must in bass.(G-E-C)

Minor Chords in Roman numerical

Major family chords can be used to create any minor family chord progression. Minor scales are created by taking the sixth note from the major scale.

As an example we take G major scale to create Em family chords:

The small Roman number for minor chords and Capital for major. For any chord sequence, it can be applicable.

Note: In order to create any minor scale, we need the 6th note from that respective scale.

Roman Numeral Chords with Slash notation added bass note

1. G major scale if we take the fourth chord which is C major and if the bass is D it can also be written in Roman numerals

C major chord -C -E -G

Bass note- D

Irrespective of the G major scale we can write it IV/5th.

In other words, normally we can write as Cadd9th (without Roman numerical)

2. Em chord with bass is A it can also be written in Roman numerals.

Em- E -G -B

Bass note- A

Irrespective of the G major scale we can write it vi/2nd.

Hence, Roman numerals can now be used to write chords.

To write Slash Chords in Roman numerals by yourself, The following points are shown

1. Keep the scale notes in mind.

2. Think about the chord respective to the key scale.

3. Check the chord’s inversion carefully.

4. Bass notes are important to write chords.

5. Major chords are in capital numerical and minor chords are in small numerical.

6. If and only if notes are not part of that chord, use numbers (1st, 2nd, 6th).

1. Keep the scale notes in mind

Scale notes must be arranged in the right sequence. D E F# G A B C# D are notes of the D major scale. It never is like D F# G B C# A E D it is wrong.

2. Think about the chord respective to the key scale

G is the 4^th chord of D Major. To find the 2^nd, 3^rd, etc. chord it must be respectful to the D major scale.

3. Check the chord’s inversion carefully

Chord’s inversion helps to understand chords.

4. Bass notes are important to write chords

Which inversion should be written depends on the bass notes.

In conclusion, observe before writing Slash Chords in Roman numerals. I hope this post clears all your doubts. Thank You.