Music theory for beginner guitarists

Most beginner guitarists start by learning the same fifteen chords, usually called the “standard fifteen.” I’ve also heard them called the open chords because they make use of open strings and are thus easy to play:

A A7 Am
C C7
D D7 Dm
E E7 Em
G G7

For fingerings, have a look at wikipedia or any book on beginner guitar. You can also see this handy web site, which plays audio of each chord along with the fingerings.

It’s not much good to just memorize the standard fifteen chords without musical context. It’s better to learn them grouped together into keys, so you can hear how they relate to each other. Family Guy explains how this works using the key of G. I apologize for the filthiness of the opening joke, but then it actually turns into a good music theory lesson.

Here are the standard fifteen grouped into various useful major, blues and minor keys. Pick a row and try the chords within it. They’ll sound good together in any order and in any combination. The first chord in each row is the tonic chord, which feels like home base.

Major keys

          I  ii  iii IV  V  vi    V/V  V/ii V/vi
C major:  C  Dm  Em  F  G7  Am    D7   A7   E7
G major:  G  Am  --  C  D7  Em    A7   E7   B7
D major:  D  Em  --  G  A7  --    E7   B7   --
A major:  A  --  --  D  E7  --    B7   --   --
E major:  E  --  --  A  B7  --    --   --   --


          I7  bIII IV7 V7 bVII

C blues:  C7  --   --  G7  --
G blues:  G7  --   C7  D7  F
D blues:  D7  F    G7  A7  C
A blues:  A7  C    D7  E7  G
E blues:  E7  G    A7  B7  D

Minor keys

          I   V/V bIII iv  IV  v   V   bVI bVI7 bVII
D minor:  Dm  E7  F    --  G7  Am  A7  --  --   C
A minor:  Am  B7  C    Dm  D7  Em  E7  F   --   G
E minor:  Em  --  G    Am  A7  --  B7  C   C7   D

For more adventurous sounds, try mixing chords from different keys together. Trust your ears and have fun!

Update: once you’ve mastered these chords, maybe you’d like to tackle the pentatonic scale.

Further update: it was pointed out to me by commenter Bruno that the roots of the blues chords spell out the minor pentatonic scale. I hadn’t even noticed that. Pretty cool.

7 thoughts on “Music theory for beginner guitarists

  1. Unfortunately I don’t, not music books anyway (I work with robotics). I’ll keep my eyes open, though. A decent book on these subjects would be a big win for the world…

  2. Thanks for this great clarification, Ethan! This is really helpful and things do make more sense now. I will read the articles you suggest as soon as I have the time. Have you ever thought of writing a book? I have no idea how come it took me so long to find out your blog. By now you should be one of the authoritative sources on the internet when it comes to teaching basic music theory to beginners. You complicate things only to the point you really need to, and covers topics in an order which makes it easier to build an intuitive understanding of otherwise difficult concepts.

    Thanks once again for taking the time to do this.


  3. Ah, that makes a lot of sense. Thank you for the very informative reply.

    One more question regarding why you chose not to list some of the chords in those keys. I understand that the vii chord is not used too often, but why did you not list some of the “intermediate” chords of the key? For instance, the iii chord on the case of G major, the iii and vi on the case of E major, etc? It seems like the degrees (is that how they’re called?) that you did not list depend on the specific major key being analyzed, and not only on the fact that they are major keys to begin with.

    Also: I’ve never heard about secondary dominant chords before; I will try to find out more about them. Any suggestions on what I should read to try to understand how the use of these additional chords modifies the roles of the “standard” chords of a key? For example, it seems like the rules of chord resolution change if you add secondary dominants: now you have different things that you can resolve to, etc. Also, I assume that the usual “feeling” you get when you play a iii chord (for instance) is altered if you add in one or more of the secondary dominants.

    Last question, if you don’t mind! (and this might be a dumb question that you may have already discussed somewhere else; apologies if that’s the case). Why are these the specific degrees that you used for Blues key?

    I7 IV7 V7 bIII bVII

    You only have 5 chords there; is this at all related to a pentatonic scale? Why are they listed “out of order” (1, 4, 5, 3, 7)?

    Similarly, in the case of Minor keys, you used

    I bIII iv IV v V bVI bVII V/V bVI7

    It seems here like you’re not just considering the same three secondary dominants as before (that is, the same ones you used in the Major keys). I only see a V/V. Which one of those chords are things that you’re adding to the standard minor key? And why is there a minor *and* a major fifth?

    Apologies for the tons of questions: yours is one of the best articles/sites I’ve found when trying to learn about these aspects of musical theory. Things are just starting to make sense!

    Thanks a lot, once again,

    • The purpose of this post was not to list all the chords in all the keys, but just to show what keys you get from the standard fifteen guitar chords. I leave out all the chords that aren’t among the standard fifteen. So that’s why I left out the iii in G major, it’s Bm, a barre chord. I did include the iii chord in C, because it’s Em, a standard fifteen chord.

      Here’s a blog post on secondary dominants that you might find useful:

      The bottom line is that secondary dominants temporarily move you into a new key. When you’re in C, the A7 chord temporarily puts you in the key of Dm. The D7 temporarily puts you in the key of G. It’s a way of introducing some dissonance and drama into the music without being totally random about it. In classical music your secondary dominants always have to resolve to the root chord in their native key, but jazz and rock are much more relaxed about such things.

      The “blues key” concept is one that I kind of invented, because classical music theory says nothing about the blues. The chords I listed are the ones that you’re most likely to encounter in a blues context. I didn’t even notice that the roots spell out the minor pentatonic scale. That’s pretty cool. I list them out of order because I, IV and V are “standard” chords in a major key, and bIII and bVII are specific to blues. But perhaps it would make more sense to list the roots in order. Here’s some more info on the blues:

      Things get to be complex when dealing with the minor keys because there isn’t just one minor scale. There’s natural minor, harmonic minor, Dorian mode, etc etc. I list the chords from each of these scales that are most commonly encountered in popular music. That’s why I list different secondary dominants from the major keys; it’s just a reflection of what you see in actual use. The issue of v and V in minor keys is a profound one. It gets at the difference between the different minor scales. The fifth chord you get from the A natural minor scale is Em, which feels weak and unsatisfying. The fifth chord in harmonic minor, on the other hand, is the dominant (in every sense) E7. It’s pretty common to see both of them together in a song. You’ll see Em, then E7, then Am, with the melody line spelling out G, G#, A. You’ll notice that I also list both the minor iv (from natural minor) and the dominant IV7 (from Dorian.) Here’s more info on all that:

      Glad I’m helping you cut through the fog. Keep the questions coming.

  4. Hi Ethan,

    Thanks for posting this. Very helpful. I’ve got a couple of questions, if you don’t mind. Why is it that, for the major keys, you don’t have a column for the vii chords? For instance, for the C major key, wouldn’t Bm be part of the progression? Similarly, why don’t you have a column for the ii chord on the Minor keys? Finally, what are the V/V V/ii V/vi chords that you list, for the case of the Major keys? For instance, in what sense is D7 part of C major, given that D (the 2nd chord) should have a minor, not major, third?


    • Hi Bruno,

      You’re welcome, glad to hear it.

      I left out the vii chords for a couple of reasons. First of all, rock, pop and blues songs just about never use them. Secondly, vii chords aren’t minor, they’re diminished (half-diminished actually.) This topic tends to overwhelm beginners, long before they need to be thinking about it. Same goes for the ii chord in the minor keys; you don’t need to know about it until you get to jazz.

      The V/V, V/ii and V/vi chords are called secondary dominants (applied chords in classical music.) Technically, they aren’t part of the key. V/V is the dominant chord in the key of V, so in C, it’s D7, the dominant chord in the key of G. V/ii is the dominant chord in the key of ii, so in C, it’s A7, the dominant chord in D minor. And V/vi is the dominant chord in the key of vi, so in C it’s E7, the dominant chord in A minor. I include them because it has become common practice in popular music to use the secondary dominants as if they’re part of the key, without regard to their function. Neil Young, for example, will use the D7 in the key of C without ever resolving it to G7 (usually he just “resolves” it back to C.) Another common practice move is to “resolve” E7 up to F, rather than to Am where it’s “supposed” to go. The rules of western music theory do a better job of explaining the music of the 1700s than the present.

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