cycle of fourths / chord progressions

So why is the cycle of fourths potentially important to the creative musician? Of all of the "cycles" available to the "modern" musician, the cycling of pitches by the interval of the perfect fourth is probably the most commonly used to create the various styles of American music. Three or four chord folk songs, a three chord rock tune, the basic 12 bar blues form all are essentially created with chords and cadential motions that move by the interval of a fourth. In more complex cycling of chords, as in jazz, the root motion by fourth is oftentimes the glue that helps keeps things together.

Oftentimes associated with organizing the 12 major / minor keys found within the equal temperament system by key signature, the cycle of fourths is often depicted in the following manner, similar to our time clock with the 12 hours, with the key of C taking the 12 o'clock position. The following diagram places all of the 12 pitches of the chromatic scale moving by the interval of a perfect fourth clockwise from C. Isn't it beautiful? Example 1.

To begin our explorations of the relationship between chords and the cycle of fourths, let's create a chord progression using the 7 diatonic 7th chords of the key of C major. Example 1a.

Looking at the bass line of example 1a, all of the root motion is by diatonic fourth. And although they are not all perfect fourths, as between bars 1 and 2, or moving upward, (down a fifth equals up a fourth right?), we have maintained as consistent a motion of fourths as diatonically possible within the major tonality, i.e., the pitches of C major. Lets compare the diagram from example one with a new one that only includes the root motion of the bass line found in the music above in example 1a. Example 2.

Moving clockwise, can you see the similarities? We've simply taken only the pitches of the key of C major from the left side of example 2a and redistributed in example 2b. Does that help in seeing the cyclical nature created by the cycle of fourths in the music above? This next musical example is just the bass line, moving in diatonic fourths in C major. Example 2c.

Cool huh? If there was ever was a way to quickly get the gist of where a tune is going to go, hearing just the bassline just might provide the window. So, what happens in the music we love to play, listen to, share with others? In many cases, a story is being told. To create a musical starting place for our story, we pick a tonal center or key, which in the above case is C. We then define it's tonal environment, usually either major or minor. This story starts and ends in the major tonal environment. Our story starts at C and as the story unfolds, we move away from C to F, to create a sense that the music is moving along with the story. As the story unfolds we move further away from F into the minor tonality through B to E, where perhaps we begin to sense that "there is no place like home." To get home to C, we simply cycle by fourth to A, then D, then G to C. Easy. When the pitches move in this fashion, players call it backpedaling. Cool?

What other common chord progressions use the root motion of the fourth? In a root position One / Four / Five to One cadential motion, we can use it twice. Example 3.

Root motion by fourth. C up a fourth to F between bars 9 and 10. G up a fourth to C between bars 11 and 12. Simple. Can you think of an important American musical style based on the One, Four and Five chords? Hint, the name begins with a B and there is a color named after it. Bbbbbbbluuees, right? Simply motion by perfect fourth.

How about the all encompassing jazz standard essential, the Two / Five / One cell? Let's look. In C major. Example 4.

Root motion from D to G in bars 13 and 14, G to C in bars 14 and 15, all perfect fourths. Lets "double up" the Two / Five into the Three / Six / Two Five. Example 6, using non diatonic pitches ( bars 17 and 18 ) as part of the motion setting up the resolution to C major. Example 5.

The diatonic root motion of E, A, D, G in the above idea simply cycles the root motion of perfect fourths. Perhaps tag one of your jazz arrangements with this cycle. The Three / Six / Two / Five is also a common intro when performing as well as being incorporated in the body of many musical compositions. Check out and learn Dukes standard "Satin Doll" to illustrate how this important cycling of chords can be used.

The power of the interval of the fourth is one worth acquiring. Do players ever exhaust and get beyond this harmonic motion of the fourth? Well, yes and no. Yes in that in jazz music, really anything goes. The more advanced jazz playing gradually becomes more chromatic, which "blurs" the tonal direction and reducing the sense of tonal gravity. Music based on more complex harmonic models is rare, but does exist. John Coltrane's "Giant Steps" is an exciting venture in this direction. One must seek to find. But in the other American styles, blues, rock, pop etc., when we move away from the basic harmonic motions as discussed here, we run the risk of loosing the sense of the style. Do players do it? Of course, that's what expanding the style is all about. The trick is to make the new level grow organically from what already exists artistically within that style. Not always, but for the most part, that is how the innovators innovate. By taking the existing resources of a style or styles and recombining these elements to create new forms of expression, the creative artist can expand and redefine the limits of a particular style. Thus, the ongoing process of artistic evolution...

Cool with the relationship between common chord progressions and root motion by fourth? Yes? Look through any written music you have and examine the root motion between the chords, chances are there will be some of the harmonic motion discussed above. Minor tonality also? You bet, here is the first example from the top of the page rewritten in the minor tonal environment. Example 6.

Cool with this? Explore the music you love looking for this motion by fourth. Bet it's there somewhere. Other topics...

"Half this game is ninety percent mental." Yogi Berra