Updated: Nov 21
Often when wanting to get into learning music theory we will eventually stumble across the cycle of fifths.
This is a good way to learn about keys and all the information thereof.
What I want to dive into today with this article is the idea that guitarists should be learning the cycle of fourths as their entry to understanding keys and key signatures.
In this article I will be discussing the main reasons why I think its true that the cycle of fourths is a better first step, they are as follows:
The Nature Of The Guitar
The reason why I bring this up is that if we look at how the guitar is constructed.
We have the strings from low to high E A D G B E. If you know anything about intervals (the spacing between two notes) you’d see the pattern of the E string going up a 4th interval to A, another 4th to D, again another 4th to G, then a 3rd to B and one more fourth to B.
Primarily most of the strings on the guitar are using 4th intervals, (except for that pesky b string!).
If that’s the case with our guitars then surely learning the cycle of fourths is a better idea? (For reasons we will get to later).
Why Are People Taught The Cycle Of Fifths First?
In most situations when you come across the cycle of fourths/fifths you will be taught to learn the cycle of fifths because this comes from the tradition of classical music and how music likes to resolve from a 5th chord to the first chord which gives that Amen sound you hear at the end of a sermon.
Its generally good knowledge to know of that perfect cadence from the 5 to 1.
The only issue being is that when we use a guitar its not built with 5ths in mind.
Often in jazz schools of thought, we teach from the perspective of the cycle of fourths for that reason and due to needing to accommodate for brass instruments. A lot of instruments are built around using the flat keys, which the cycle of fourths enables. Which brings me onto the next topic.
What Is The Cycle Of Fourths?
The cycle of fourths is a method comprised by Starting at C with no sharps or flats and going up a 4th from C to F and going up a fourth from F to Bb and so on until you can get back to C.
The interesting thing to note about learning the cycle of fourths is that every fourth note of the next key is your new flat note to account for. For example, if we want to know the next key, we can jump to from F going up a fourth it would be B flat and b flat exists in the F major scale.
This is useful to know so you can learn your major scales in accordance to the key you want and in contrast to C major where there are no sharps or flats. If we did the cycle of fifths, we would have to understand that in each key we move around in fifth intervals we would have to add the previous major 7th as the new sharp note.
I don’t think this is as easy to digest as the cycle of fourths pattern.
One of the most important things about learning the cycle of fourths and fifths is that if you see the chart in Example 1;
Using this chart outlined in Example 1 you can begin to understand that when you pick a key and you want to change into another key from the current key you have chosen, you can see which keys are close to your original key and which are far away.
This is important because the cycle is a guide to how close of a relationship each key has with how many notes they share.
The feeling it generates from doing a key change that is close together is much more agreeable than to say key change to a key that is further away as the further you go away from the original key the more the notes change.
If we use the key of C and want to change to the key of F there’s only one note change from B to B flat. That transition to the new key should sound seamless due to not many alterations being made this is due to both of those keys sharing similar chords.
If we start from C again and we go to the key of D flat we have altered 5 notes and because of those alterations it sounds much further away from the original key.
A lot of the chords don’t share the same commonality either which may sound a lot more jarring than the transition to F.
There are many ways to use the cycle of fourths/fifths but this is the most practical and useful I find.
The Practical Application Of The Cycle Of Fourths
From my experience in working with cover bands/ function bands you start to pick up skills that allow you to analyse the music of common hit songs.
A lot of them and I mean a lot of them have the resolution of going up a fourth. This maybe due to how the guitar is constructed as its an easy change from one string to the next keeping similar guitar shapes.
This is also why a lot of common chord progressions happen and a lot of them are 1 4 5s. it’s the KISS mantra (keep it simple stupid), or the Occam’s razor for understand how hit tunes get made.
To be more specific its usually the jump from the E string to the A string that most of these chart songs deal with. Seeing as we are going from the E to the A which is a fourth, the usual chord shapes we would be using (from CAGED) would be the E shape going to the A shape.
A common compositional move that a lot of 80s ballad songs have is to key change up a fourth for this very reason.
It usually happens when the outro is happening to give it more energy and a better send off. My estimation is that it’s because of the nature of the guitar.
I hope this article served well in explaining why we should use the cycle of fourths when it pertains to the guitar.