The 3 Chord Theory

The basic song comprises of 3 chords called

Primary Chords

Primary chords are the chords based on the

1st 4th 5th notes from the Diatonic Scales

Often written in roman numerals....I   IV    V

Primary chords are often played as Major or 7th chords but can be anything,

the Vth is often played 7th and leads back to the Root

You could of course just play Power (5) chords which makes it even easier!

To expand the song add Secondary Chords

these are 2nd 3rd 6th of the diatonic scale

written as    II     III    VI

Secondary chords are often played Minor or 7th but can be otherwise

for example:

Primary Chords in A =  A  D  E7

Primary Power Chords in A =  A5 D5  E5

(some)Secondary Chords in A = Bm  C#m  F#7