In the last couple of lessons of this music theory clinic, we discussed chord scales, and identified the chords that exist in a given key using the Roman numerals I – VII (1 through 7). Now we’re going to start looking at how these chords can be strung together to form a chord progression.

First of all let’s just make it clear that there are no real limits on how you put together chords in a song. Any chord can really follow any chord, and nobody is going to be standing there saying that you can’t put chords together the way you did. Analyze a Nirvana song and you’ll quickly see that there doesn’t have to be any real music theory logic in a progression for it to work. The only thing that really determines if a progression is “right” is if YOU think it sounds good. That’s the whole idea of being creative in music.

But there are sequences of chords that sound particularly good together, and there are certain patterns that we see over and over in the music we listen to every day. The people who wrote the music may not have even been aware of the “theory” that’s operating in their chord progressions–they just thought it sounded good that way. But it might just happen that the reason it sounds good is because it follows the conventions of chord progressions. In this lesson, we’re going to take a look at one of the most important conventions, the I – IV – V chord progression.

I – IV – V:  The “Primary Chords”

In the lessons about chord scales, you may have noticed that there are three major chords within any chord scale. These are the chords built off of the 1st, 4th, and 5th degrees of the scale, and they are sometimes referred to as the “primary chords” in that key.  More commonly, though, they’re just called the I, IV, and V. You may have already heard of a I-IV-V chord progression, and if you’ve played guitar at all, chances are you’ve already played I-IV-V progressions a lot.

Let’s use the key of G major as an example.  The chord scale for the key of G major is:

Looking at the I, IV, and V, we have G, C, and D. We could probably come up with a list of about a million songs that are made up exclusively with these three chords, and chances are you already know a few. This would be especially true for in folk, country, and blues music. And if a song is in they key of G, it may have some of the other chords in it (and maybe even some that don’t come from this chord scale), but chances are that all three of these chords make regular appearances in the progression.

V to I: The most important concept in music

If you wanted to boil the entire universe of music theory down to one simple sentence, it would be this: the V chord goes, or “resolves,” to the I chord. That’s the whole deal right there. Most everything that happens in music happens around this concept. It’s especially true if the V chord is a 7th chord.  So in the key of G major, as in the example above, the D7 chord would resolve back to the G.  Below are a couple of examples for you to check out and listen to.  Note the fact that V7 resolving to I sounds the same regardless of what key you do it in.

It’s also worth noting that a V chord doesn’t HAVE to resolve to the I chord.  It just WANTS to resolve to the I chord.  But like everything else in music, you don’t have to obey this rule, you just have to know it.

I, IV, and V in other keys

I strongly recommend that all guitar players, sooner or later, memorize the I, IV, and V in all of the keys.  Start with the common keys, like A, C, D, E, and G.  Once you know those, it’s not too hard to figure out the rest–if the I, IV, and V in the key of A are A, D, and E, then it’s pretty easy to figure out that the I, IV, and V in the key of Ab are Ab, Db, and Eb.

You can always refer to the table of major scales for this information, but I’ll save you the trouble by listing the I, IV, and V in all the keys:

Songs made up exclusively of I, IV, and V

Like I said, we could probably come up with a million, but a few examples off the top of my head:

• “Twist And Shout” by the Beatles (I, IV, V in D)
• “Folsom Prison Blues” by Johnny Cash (I, IV, V in E)
• “La Bamba” by Richie Valens (in C)
• “Wild Thing” by the Troggs (in A)
• “Dead Flowers” by the Rolling Stones (in D)
• “Rock And Roll” by Led Zeppelin (in A)
• “Still Haven’t Found What I’m Looking For” by U2 (in D)
• Just about any country/folk/bluegrass tune you can think of
• Just about any 12-bar blues song you can think of.