When you're improvising over chord changes, you can get a lot of clues about which notes to play from the chords themselves. To help you do this, it is useful to understand how chords are structured.

Every chord has a root, a third, and a fifth. These terms refer to the scale degree; that is, the notes that appear at the first, third, and fifth places on the scale form the chord. If you're looking at the key of G, the scale degrees would be:

Here is the way three of the types of chords already discussed in this book are structured and what the notes are in the key of G:

Note that the common factor between all three chord types is that they all share the same root and fifth notes. This means that the root and the fifth are two notes that will appear and be the same exact notes in any chord with the same letter name. And that means they are both go-to notes you can play over virtually any chord. Bass players rely heavily on roots and fifths to create their bass lines for this very reason.

If you're trying to figure out what the root of a chord is, you don't have to look far — it's the same as the name of the chord. The root of a C-major chord is C, the root of an E7 chord is E, and so on.

When you're going to improvise over a chord progression, before you begin take a moment to identify the roots and fifths of the chords in the progression, and then find those notes on your harmonica. This will give you a structure of notes on which you can build your solo.

You may have heard musicians talking about a 1-4-5 blues progression. The numbers 1, 4, and 5 refer to the notes of the scale you are playing in. You are playing in the key of G in the following examples of 12-bar blues, so the notes of the scale are G, A, B, C, D, E, F#, and G. The fourth note of the scale is C, the fifth note is D, so the chords of your 1-4-5 progression will be G, C, and D. Now you'll hear a G, a C, and a D on the C harmonica.

FIGURE 11-1: Roots, fourths, and fifths

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