Roman Numerals and How to Play a Chord

Chord progressions are a good way to remove composer’s block, where you stare at the keyboard and can’t think of anything to compose. A chord progression is the movement of one chord to a subsequent chord in a repeating fashion. They can be of any length, but the most common length of a chord progression is 4 chords. Chord progressions are used to add harmony to the composition. The underlying harmony of a piece can change the entire mood of the composition.

Before we begin, I would like to explain Roman numerals, which are used to notate chord progressions. Below you will find a table that lists how roman numerals and chords correspond in the C major scale.

C major	D minor	E minor	F major	G major	A minor	B diminished
I	ii	iii	IV	V	vi	vii°

The Roman Numerals are widely used because they allow the composer to start on any note. If you wished to start on the key of D instead, then D major would become your I chord. Likewise, if you wanted to start on the key of F sharp, then F sharp major would be your I chord. Roman numerals allow the composer to start on any major scale.

A traditional major chord is composed of a minor third on top of a major third. For example, C major is C, E, G. C to E is a major third and E to G is a minor third.

A traditional minor chord is the opposite. It has a major third on top of a minor third. For example, D minor is D, F, A. D to F is a minor third and F to A is a major third.

Varying between major and minor chords in the harmony is a great way to create contrast between sections. For example, in one section you might employ the basic I, IV, V progression, where each chord is major. The next section could be composed of all minor chords such as ii, vi. Twilight March is an example of one of our songs that uses this idea to add contrast between the sections.