Guitar Chord Numbering

To organize chords, we can utilize a guitar chord numbering system. We name a particular chord, the one chord (also known as the tonic). Once a chord is named the one (I), it's alphabetical from there. So, if A is the one chord, D is the four chord (IV), & E is the five chord (V). If A is 1, D is 4, & E is 5.

In popular music, the I, IV, & V chords are commonly used chords, & you should memorize the them for every key.

The I chord is called the Tonic. The IV chord is called the Subdominant. The V chord is called the Dominant.

Tonics like to move to Subdominants. Subdominants like to move to Dominants. Dominants like to go to Tonics. When chords follow this progression ( I to IV to V to I), this is considered progressive harmony (regressive being the reverse).

Progressive Harmony moves like this…

The Subdominant

The subdominant is called the subdominant because it is the dominant below (5 tones below), not because it is one under the Dominant.

Tonics (I), Subdominants (IV), and Dominants (V)

These following chords are triads (3-note chords).

These triads can be used for most styles, but if you were to follow the blues progressions, you need to add the flat 7 to these chords to get the blues sound.

Particular styles use particular voicings. The voicings (the ways we sound chords - we have choices) below are perfect for folk, country, rock ballads, etc.

I, IV, V for All Keys

Guitar chord numbering is a great way to keep track of relationships between chords. It is important to memorize (move information to pure knowledge) the relationships between chords.

Practice playing the blues progressions by substituting these triads in those progressions.

And, memorize the relationships, starting with C, G, D, A, & E (main 'guitar keys').

Apply guitar chord numbering in all keys (I ii iii IV V vi viio)