Introduction to Chords Substitution

Hi,

This post is an attempt to understand basic chords substitution.

This is useful when the chords for both the verse and chorus of a song are the same.

Let's list down the chords in G major.

I II III IV V VI VII
Gmaj7 Am7 Bm7 Cmaj7 D7 Em7 F#m7(b5)

For example, the chords of a song uses I VI IV V progression.

The chords will be Gmaj7 Em7 Cmaj7 D7.

We can substitute I with III.

Instead of playing Gmaj7, we change to Bm7.

The new progression will be Bm7 Em7 Cmaj7 D7

The notes in a Gmaj7 are G B D F#

The notes in a Bm7 are B D F# A

Out of 4 notes, 3 are the same, therefore it will sound correct.

Hope this helps.

Have fun.