Introduction to Basic Chord Theory

Often referred to as the "Nashville System"

This simple system will help you learn chords faster and help you play in different keys. If you're smart you won't skip this...

The core concept of Basic Chord Theory (or The Nashville System) is that you can play along with many popular songs by learning just a limited number of chords for each key a song is played in. These chords follow a specific pattern, and that pattern is the same for all keys. It is called the 1-4-5 pattern.

Let me explain...

When a song is written in a specific key, the notes used in that song are taken from the major scale it is based on. For example, when a song is written in the key of G, the root note is G, and the notes in the song are taken from the G Major scale.

Each of the notes in a major scale are given a number. For example, for the C Major Scale the note C is the 1 note. D is the 2 note, E the 3 note, and so on.

The chords that "fit" a song written in a specific key are based on and are rooted in the notes of the scale. These chords are referred to by their root note. For example, for a song in the key of G the G Major Chord is the "1 Chord", C Major is the "4 Chord", and so on.

What is the Pattern that works for most songs?

As already mentioned, the pattern is known as 1-4-5. The chords for each key are the "1" Chord, "4" Chord, and "5" Chord. This is often written in Roman Numerals: I-IV-V. So, for a song written in the key of C, the I Chord is C, the IV Chord is F, and the V Chord is G

This makes it easy to strum along with many songs, simply by using the I, IV and V chords (in the appropriate places in the song.) Often a song will include a minor key as well. It will usually be the 2 (ii) or 6 (vi) chord. For the key of C these additional minor chords are E minor (ii) and A minor (vi).

Here is a chart of the important chords for three popular keys:

1-4-5 Part 2 - A deeper explanation

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