About the I, IV, V and vi Chords

In several past episodes the same topic has come up: a way of thinking about chords that makes it much easier to play by ear, improvise, and get an instinctive feel for what’s going on in the music you hear. Steve Myers, Sara Campbell, Shelle Soelberg, Casey McCann, Lisa McCormick, Scott Sharp – all these guests have mentioned the “one, four, five and six” chords.

The band Blues Traveler even start one of their hit songs by declaring it’s “Just another 1, 4, 5”.

So what are those chords and why do they matter?

This is one of the most valuable things to wrap your head around in music. And if you don’t play chords on your instrument, please don’t tune out! Understanding how harmony works can help you improvise melodies, it can help you write your own music, it can help you decipher music notation and sight-read more easily. It’s that fundamental.

What are the 1, 4, 5 and 6 chords?

Simply put, when people talk about chords using numbers like this they are just referring to chords relative to the key, the tonic note. It’s a shorthand for the role that each chord plays in a key – and the things people say about chords using numbers are true in any key.

In a recent episode we talked about finding chords in scales – and that’s exactly what we’re doing when we talk about the 1, 4, 5 and 6. It’s taking that number note from the key’s scale and building a chord on it.

Let’s get concrete for a moment. The power of this system is that it abstracts away from the particulars of any one key – but that can also make it a bit confusing at first.

Supposing we’re in the key of C Major. Note 1 in the scale is C. Note 4 is F, note 5 is G and note 6 is A. As covered in that previous episode we can build a three-note chord called a “triad” starting from each of those notes.

When we do this from the note C we get the C major chord, and that’s our “one” chord. From the F note we get an F major chord and that’s our “four” chord. From the G note we get a G major chord and that’s our “five” chord. And finally from the A we actually get an A minor chord, and that’s our “six” chord.

Can we build chords from notes 2, 3 and 7 too? Of course! But we’ll talk in a moment about why those aren’t the ones we’re focusing on right now.

So we can build these four chords from the scale, and we can do that in any key.

If we do it in the key of G Major instead of C Major we end up with G major as our “one”, C major as our “four”, D major as our “five” and E minor as our “six”.

We’ll definitely be talking about the Circle of Fifths in a future episode because that’s a terrific way to shortcut this process of figuring out the chords in any key without needing to count through notes of the scale. But for now just know that you can figure out what these one, four, five and six chords are in any key. The one, four and five will always come out as major triads and the six will always be minor.

So what’s the point of all this?

Why the 1, 4, 5 and 6 chords matter

In our episode on The Power of Solfa we talked about how naming or numbering the notes of the scale relative to the root note is helpful because it gets us away from all the letter names and sharps and flats that vary in every key, and gets us directly to the way we actually hear music. We interpret notes relative to the key’s tonic, and so naming notes in that way makes it far easier to start understanding what’s going on in the music you hear.

Exactly the same is true of chords. When we abstract away from any one key and talk in terms of these chord numbers we get straight to the heart of how harmony actually works and how our ears are interpreting the chords we hear.

Here are a few questions you might have found yourself asking about chords:

• Why do these chords sound good when I play them after each other but those other ones don’t?
• How can I know what chords to choose when I’m writing a song?
• If I want to play a song in a different key than the sheet music or recording I have, how do I know what chords to play?
• Why do so many pop and rock songs sound kind of the same even though they have different melodies?

All of these questions can be answered easily when we think in terms of chord numbers – but they all get very complicated if you only think about the literal names of chords in different keys.

For example: The one, four and five chords are the most commonly-used chords in almost every genre of music, with the six chord following shortly after. That means that a ton of music we hear each day is using just those chords.

If we only thought in terms of keys and chord names that wouldn’t be obvious. We’d be able to hear that the songs’ chord progressions sounded kind of similar but they’d all have different chords so it wouldn’t be clear why. When we translate those chords into this one, four, five, six naming system it’s immediately obvious: they are all using exactly the same chords, just in a variety of keys.

That is a massive shortcut if you want to train your ears to recognise chords. Because really what you want to learn isn’t “how can I hear a C-G-A minor-F progression?” – it’s “how can I hear a 1-5-6-4 progression no matter what key it happens to be in?” Your ears really don’t mind what key is being used and so you can quickly train them to hear that same pattern in any key.

So the one, four, five and six chords matter because they are the most frequently used in music, and thinking about them in this numbered system matters because it lets you focus on what’s actually going on harmonically and how your ears are actually interpreting the chords musically.

The next question we have to tackle is…

Rome or Nashville?

As I’ve been explaining this I’ve just been saying “one”, “four”, “five” and so on. But when it comes to writing the chords down there are a couple of different systems.

The first is the Nashville Numbering System. Super simple, we literally just write down the number. The number “1” for one, the number “4” for four, and so on. Generally the major/minor quality of the chord is assumed based on what’s normal for the key, so for the “six” chord you just write the number “6” and the musician reading it knows that’ll be a minor chord.

The second system looks intimidating but is just as simple. It’s to use Roman numerals for the chord numbers. We write a capital “I” for the one chord, a capital “I” followed by a capital “V” for the four chord, a capital “V” for the five chord, and a lowercase “v” and “i” for the six chord. That can look weird if you’re not used to Roman numerals but actually that weirdness is part of its advantage. We use numbers for lots of different things in music but we only use Roman numerals for naming chords like this. So when you see these symbols written down you immediately know that it’s referring to chords in the key. You still say them out loud as “one”, “four”, “five” and so on.

Start using the 1, 4, 5 and 6

So now you understand what the one, four, five and six chords are. You can start taking advantage of this immediately. Next time you’re playing a piece of music ask yourself what the numbers are for the chords being used. You might be surprised how often it boils down to just these three or four chords. That’s why you might hear people talking about “3-chord songs” and “4-chord songs”.

The next big step is to start learning to recognise these chords when they’re used. As I said before, you have a huge shortcut here because you know you’re just looking for the same patterns, no matter what key is being used. We have a whole Roadmap and set of modules for learning to recognise and play chords by ear in Musical U and it’s centered on this insight: that focusing on just the one, four, five and six chords actually covers a huge amount of ground.

Yes there are other chords that can be used, and yes the types of chord can go beyond just major and minor. But get your mind and ears wrapped around the one, four, five and six chords and you’ve got the best possible foundation for understanding and recognising each and every chord you hear.

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