Basic Chord Theory

A beginning guitarist is often overwhelmed with learning chords.  A common method is to memorize the forms of chords in the first position (chords formed by using the notes contained on the first three frets).  However, if guitarists wish to move beyond the fundamentals it helps to have a basic understanding of chord theory.  In this lesson we will review the fundamentals of major and minors.  Other chords such as major sevenths, and major and minor dominated sevenths, augmented, suspended, half-diminished (also called minor flat 5), diminished sevenths, 6th, 9th, 11th, and 13th chords, we will cover in other lessons.  Some musicians refer to these latter chords as the ‘jazz’ chords.

A chord is two notes played simultaneously.  However, a two-note chord is ambiguous.  Is it a major, a minor, a major seventh, a dominant seventh, etc.?  There are many situations when playing a two note chord is desirable such as when playing in an ensemble where to the other musicians play the remaining notes that define the chord.  It is also common in rock (power chords) and in blues.  A chord we can name typically has three or more notes. 

Chords follow specific formulas.  We will start with major and minor chords.  I will use the C chord (root note C) as an example but the formulas apply to any chords built upon any other root note.

Major Scales and Chords

We’ll start by examining the C Major scale.  There are many types of scales; however, here we are only concerned with Major and Minor scales.

The C Major scale is …

C Major Scale

This is the common eight note Do Ri Me scale – Do, Ri, Me, Fa, Sol, La, Te, Do.  It is also called a diatonic scale.  It follows a defined pattern of steps (the distance between two notes in the scale).  One whole step (W) equals two frets while a half step (H) equals one fret.  The pattern for the major scale is W,W,H,W,W,W,H.  If you follow this pattern starting on any root note, it should sound like Do, Ri, Me, Fa, Sol, La, Te, Do (remember the song from the Sound of Music).

We can number the notes of scale from one to eight.  We call the span from one root note to the next root note an octave-Latin for eight.  Chords such as 9ths, 11ths, and 13ths have tones that go beyond the first octave.

Major Chords

The formula for a major chord is 1 (root note), 3 (third tone), and 5 (fifth tone).  In the key of C this is C, E, and G.  We denote a major chord by its root note – i.e. C.

C Major Chord

Notice in the example above that even though you play five notes every note is either a C, E, or G.

Challenge to Students

Using the formula for a major scale (W,W,H,W,W,W,H), what are the notes in the G Major scale (a # – sharp scale) and in the G Major Chord?  What are the notes in the F Major scale (a b – flat scale) and the F Major chord?

Minor Scales and Chords

There are several variations of the minor scale – relative/natural, harmonic, and melodic. They all have a flatten the 3rd in common. Here we will discuss the relative/natural minor.

All major scales include relative minors. These are also referred to as natural minors. The relative minor begins on the sixth tone of the major scale.

For example in the key of C Major, the sixth tone is A.

C Major Scale

If we began and end playing this scale on A, we’ll play an A natural minor scale.

A Natural Minor

Note that this scale contains a flattened third (b3), a flattened sixth (b6). and flatten seventh (b7). This is because, for numbering purposes, we relate this scale back to A major. If we follow the formula for a major scale – W,W,H,W,W,W,H – for the key of A, we end up with – A, B, C#, D, E, F#, G#, A. In the A minor natural scale C# becomes C, F# becomes F, and G# becomes G# – all flattened by one half step in relation to the A major scale.

The formula for the natural minor scale is therefore – W,H,W,W,H,W,W. Recall that W – a whole step – is 2 frets on the guitar while H – a half step – is one fret on the guitar.

Major Chords

The formula for a minor chord is 1 (root note), b3 (third tone), and 5 (fifth tone).  In the key of A this is A, C, and E.  We denote a major chord by its root note followed by a lower case ‘m’ – i.e. Am.

Am Chord

Finally, before we leave this topic, notice how the C and Am chords share two notes – C and E

Challenge to Students

Using the formula for a major scale (W,W,H,W,W,W,H), what are the relative minors for G Major and F Major?

Using the formula for the natural minor scale W,H,W,W,H,W,W, what are the notes for those two relative minor keys?

What are the notes for tonic chords for the those two minor keys? Tonic is another name for the 1 or key tone in the scale. In the natural minor example I presented above this was A and the associated chord was Am.