I dont understand how roman numerals work - Tomo Fujita Guitar Wisdom Forums

Hi Roger,

In the Major scale each note is assigned a number using Roman numerals, these are called the ‘scale degrees’ C=I, D=ii etc. see below

I ii iii IV V vi vii
C D E F G A B

Now you will see that some of the Roman numerals are upper case and some are lower case, the upper case ones are Major and the lower case ones are minor except for vii which is diminished. So the chords in the key of C would be:

Cmaj Dmin Emin Fmaj Gmaj Amin Bdim

The Roman numerals can now be used to describe a chord progression, for example a simple blues progression might be:

I IV V so in the key of C this would be Cmaj Fmaj. Gmaj

I IV I IV V would be Cmaj. Fmaj. Cmaj. Fmaj Gmaj

I IV V vi would be Cmaj Fmaj. Gmaj Amin

This works exactly the same fir every key.

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Felipe Restrepo

almost 5 years ago

And how do you know which notes aremaj or min in different scales or is the same I ii IV V vi vii for every scale?

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Elsky Omer

almost 5 years ago

You can get the major and minor by the triads of each degree of any Key.

In key of C (C major scale), the notes are C D E F G A B

You get the C major sound when you stack the 1-3-5 which are CEG
You get the D minor sound when you start from D (1) and its 3-5 which is F-A
You get the E minor sound when you start from E (1) and its 3-5 which is G-B... and so on

The D and E above are the 2nd and 3rd degree of C if you're in key of C, not to be confused with D and E majors if you are in their respective keys which have their own set of notes.

In key of D (D major scale), the notes are D E F# G A B C#... so the 1-3-5 of each degree are:

D - DF#A = (Major)
E - EGB = (Minor)
F# - F#AC# = (Minor)... so on..
C# - C#EG = (Diminished)

To get the 7th chord, just add the 7th note, so in key of C, the 1-3-5-7 is CEGB which is Cmaj7.

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ROBERT HART

almost 5 years ago

Hi Felipe,

It's the same sequence for every major scale.

Just to be clear, the notes themselves are neither Major nor Minor. Major and Minor tonality is only achieved when you put three or more notes together as Mhel Rome describes.

C Major scale in Notes - C D E F G A B

C Major scale in Chords - Cmaj Dmin Emin Fmaj GMaj Amin Bdim

D Major scale in Notes - D E F# G A B C#

D Major scale in Chords - Dmaj Emin F#min Gmaj Amaj Bmin C#dim

You can build any Major scale by starting on the root note and counting - Whole-step, Whole-step, Half-step, Whole-step, Whole-step, Whole- step. Where Whole-step=2 frets and Half-step= 1fret.

Once you know the notes in each scale you can apply the roman numerals to work out what chords are in that key, then you can use the common progressions or create your own.

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