Music Theory for Harmonica Players

Music Theory for Harmonica Players Part 9 – Introduction to Chords

A chord is simply a certain number of notes played at the same time. Guitar players do this by strumming, piano players hold down several keys at the same time. On the harmonica we simply need to blow into a few holes.

The chords played in a song represent it’s basic structure. Songs have a chord pattern that they follow (usually quite a repetitive one) along with the rhythm and melody. Although the harmonica is probably most commonly thought of as a single note instrument it’s essential to understand chords to play along with other musicians. When playing as part of a group you need to know that the notes you’re playing will match the chords the band are playing, otherwise you’re going to clash, sound horrible and likely get kicked out of the band.

We’re going to look at a few simple chords called Major Triads. They’re called Triads because they’re made up of three notes, and major because they are major sounding, as opposed to minor.

We’re going to build chords based on the G major scale so let’s look at that again, along with the scale degrees (refer back to the posts on building major scales if you need a refresher).


G Major Scale:         G A B C D E F# G
G Major Scale Degrees: 1 2 3 4 5 6 7  8/1

To make a G major chord we simply combine the 1st (also called the Root Note since it’s the base of the chord), 3rd and 5th notes. G B D

On our C harmonica (remember why we always reference a C harmonica?) we have these notes available on holes 1, 2 and 3 draw. So drawing on holes 1, 2 and 3 at the same times gives us a G chord. They’re out of order but because we’re playing them simultaneously that doesn’t matter.

We’re going to give this chord a number and represent it with a roman numeral. This is the I chord.

Hopefully that should be pretty straightforward. Let’s do the same with C. Here’s the C Major Scale:


C Major Scale:         C D E F G A B C
C Major Scale Degrees: 1 2 3 4 5 6 7 8/1

Again we build the major chord by taking the root (1st), 3rd and 5th. C E G. Happily, these notes are available on holes 1, 2 and 3 blow. By blowing holes 1 2 and 3 at the same time we get a C chord. Cool.

Here’s something else cool. Because you’ve memorised the notes on the C harmonica (seriously, you have done that by now, right?) you know that the C E G pattern repeats 3 times across the blow holes. That means that you can blow pretty much anywhere and get a C chord, or at least something close enough to get away with. That’s a very useful bit of knowledge to tuck away for later.

We’re going to number this chord IV because C is the fourth note of the G scale we’re working from. Check the G major scale above if you don’t believe me. Here’s the IV chord added to our diagram.

The final chord we’re going to look at is D. We use exactly the same procedure again and pull the 1st, 3rd and 5th note of the D major scale.


D Major Scale:         D E F# G A B C# D
D Major Scale Degrees: 1 2 3  4 5 6 7  8/1

So our D Major chord is: D F# A. We call this the V chord because it’s built from the 5th note of the G Major scale we started with.

We run into a problem with the V chord because we can’t easily access it on our harmonica like we can a G or C chord. This means that when we try to match the V chord in a song we need to rely on single note playing. It’s awkward, but it can lead to some inventive and interesting sounds in practice.

Here’s the D added to our chord diagram.

It would be fair to wonder why we’ve picked these chords specifically out of the scale to examine. The reason is that these are the chords most commonly used in blues, folk and country music. Thousands and thousands of songs are put together using just these chords so it’s essential to get to grips with them first.

In this series of posts we’re going to be focussing primarily on blues, but be aware that the chord theory applies whatever genre you’re playing.

We’re going to have a look at how a typical blues is constructed and how we can play along with it over the next few posts. But first there’s another very important type of chord we need to look at – 7th chords. That’s coming up next.