The Very Basics Of Music Theory For Guitarists

Here’s a guest post we did for Bobby – The Guitar Answer Guy

This one is The Very Basics Of Music Theory For Guitarists



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Music Theory Part 9 – Minor Scale 4 Note Chords

Welcome to Part 9 in our series on Music Theory.  This time it’s about Forming 4 note chords in a minor key.

This is where we refer back to the post about Relative Major/minor scales and keys, and 3 note chord formation: Major and minor.

In exactly the same way that we would jump to degree 6 of the Major scale to begin the minor scale,

eg.  Major  C   D   E   F   G   A   B
minor  A   B   C   D   E   F   G

We can do the same when extracting 4 note chords.

ie.  The formula for 4 note chord types in a minor key is the same as in the major key starting from step 6

Therefore,  Major Key –     Imaj7     IImin7     IIImin7     IVmaj7     V7     VImin7     VIImin7b5

minor key –     Imin7    IImin7b5  IIImaj7     IVmin7    Vmin7  VImaj7    VII7


It is important to learn and know these formulas from memory and independently of each other.  Their relativity is purely something to fall back on if you forget something about them, and something to understand of their origin.

Next time in the Music Theory Series – What are Sus chords?

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Music Theory Part 8 – Major Key 4 Note Chords

We learned in parts 1-6 about Major Scales, Minor scales, Chord formation, Keys and Relative Keys.  Revisit these earlier posts if you need to, as from now on in our Music Theory series we’ll be presuming these things to be known.

Today’s post is about the 4-note chords that can be formed from the Major and Minor Scales.  These are very often called “7th chords” as, whereas basic triads are made of root, third and fifth, 4-note chords are formed of root, third, fifth and seventh.

Again though, this “root, third, fifth and seventh” is relative.  What we mean by this is that when you’re building a chord from the D note in a C major scale (ie. from step 2 of the C major scale).  Effectively you’re using notes 2, 4, 6, and 8 from the C major scale.  However, when discussing the chord, we would still always call the notes the 1, 3, 5 and 7.  ie.  Relative the the root of the chord and not the parent scale.


4-Note Chord Formulas
I,  III,  V,  VII  =  Major7
I,  III,  V,  bVII  =  7
I,  bIII,  V,  bVII =  minor7
I,  bIII,  bV,  bVII  =  min7b5  (aka  1/2 diminished)

C Major Scale  

C  D  E  F  G  A  B

CEGB =  Cmaj7
DFAC  =  Dmin7
EGBD =  Emin7
FACE  =  Fmaj7
GBDF  =  G7
ACEG  =  Amin7
BDFA   =  Bm7b5 / 1/2dim

Above, see the 4 note chords are extracted from the Major scale in the same way as the 3 note chords, (ie. using every other note).
Again, as with all the previously studied chord formation, scales, etc, this is general and formulaic.  So we can expand this to:

Major Scale 4-note Formulas
Imaj7           IImin7          IIImin7           IVmaj7          V7          VImin7          VII m7b5

Coming Next Time – Minor Scale 4-note Formulas.

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Music Theory Part 7 – Summary/Recap of Parts 1-6

Welcome to Part 7 in Bruce Music‘s Blog Series On Music Theory.  This part is a brief recap of the main points covered in the first 6 parts.  Be sure to check out those previous instalments if there’s anything here you’re unsure of.

  • The 12 notes in music –   C    C#/Db    D    D#/Eb    E    F    F#/Gb    G    G#/Ab    A    A#/Bb    B
  • Distance between each note = semitone (one fret)
  • Two semitones = A Tone.
  • Major scale formula = T  T  S  T  T  T  S
  • Minor scale formula = T  S  T  T  S  T  T
  • Pairs of relative Majors/Minors = A Major scale and the minor scale starting from the Major Scale’s 6th note = relative major/minor pairing
  • Chords are formed of a Root, 3rd and 5th.  Root gives the chord its name, 3rd determines if it’s Major or Minor, and 5th solidifies the chord
  • Formula for chords in a major key (One chord starting from each step of the major scale) = IMaj  IImin   IIImin   IVmaj   Vmaj   VImin  VIIdim
  • Formula for chords in a minor key = Imin  IIdim   IIImaj   IVmin   Vmin  VImaj   VIImaj

Hopefully these bullet points have triggered your memory.  But this is merely a brief revision.  Don’t forget to look at the full series if you haven’t already, or if you need a more detailed reminder.


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Music Theory Part 6 – The Minor Key Chord Formation

Welcome to part 6 in Bruce Music‘s blog series on music theory.  As always, if there’s anything here you don’t understand, check back through parts 1-5, as you can guarantee it’ll be covered there.

This part is on The Minor Key, and chord formation from the minor key.  The below follows on very directly (and refers a lot to) from part 5 : The Major Key and chord formationso make sure you get to grips with that first.

So, as discussed in previous posts, the minor scale formula is :  T  S  T  T  S  T  T
This is the same formula as if you started from the 6th step of the major scale. (This links into the concept of Relative Major/Minors).  Chord formation works in exactly the same way as a Major Key, ie.  root, miss one, third, miss one, fifth.

So the bottom line is, given that the minor scale is the same formula as the major scale from the 6th note, we can assert that the formula of chord types in a major key is the same as the major scale from the 6th chord.  To clarify what this means, let’s look at it in detail.

Major Key Chords – Imaj   IImin   IIImin   IVmaj   Vmaj   VImin   VIIdim

(The VImin is highlighted as this is where we start our minor key formula from.  Thus it is as below)

Minor key chords – Imin   IIdim   IIImaj   IVmin   Vmin   VImaj   VIImaj

Again, this formula is all-encompassing, ie.  take a minor scale, the chord built from the first note is minor, from the second is diminished, from the third is major and so on, without fail, exactly replicating the major scale from note 6.

You should learn and know these two formulas, but also understand their relationship to each other to support the knowledge.


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Music Theory Part 5 – Chord Formation And The Major Key

Welcome to Part 5 in our educational music theory series.  This post will cover forming chords from the Major scale.  If you’re new to the Major scale, check out part 2.  We’ll be looking at basic chords, made of 3 notes.  These are called triads. The 3 notes are:

  • “Root” – Gives the chord its letter name, ie. a C Major chord’s root note is C.
  • “Third” – Determines if the chord is major or minor.  2 tones away from the root = major third, major chord.  3 semitones (ie. a tone and a half) away from root =  minor third, minor chord.
  • “Fifth” – Solidifies the chord.  Typically 7 semitones, or 3 and a half tones away from the root.  Can be sharpened or flattened to create different types of chord, more on this later.

In practice, finding the 3 notes required to form a chord is very simple.  From your root note, skip the next, the next is your third, skip the next, and the next is your fifth.  So let’s do this now with the C Major Scale.

        I       II       III        IV        V       VI       VII
       C      D       E         F         G       A        B

  • So, with C as our root note, we skip the D, to find E as our third (2 tones away from C so thus a Major third)  then skip the F to find our fifth, G.  And there we have a C major chord.  C, E, G
  • Now with D as our root, we skip the E, to find F as our third (3 semitones away from D so thus a minor third) then skip the G to find our fifth, A.  So there we have a D minor chord.  D, F, A

We can continue this process for every note in the scale, and finish up with each scale step now representing a chord as well as a note.  This is essentially what a “key” is.  A key is a group of chords that ‘belong together’


  • The C Major scale contains the notes C, D, E…….etc.
  • The key of C Major contains the chords C Major, D minor, E minor…….etc.

So the resulting chords, the chords in the key of C Major, are –

I               II              III             IV              V             VI              VII
Cmajor     Dminor     Eminor     Fmajor     Gmajor    Aminor    Bdiminished

We’ll cover “diminished” chords in more detail at a later date, for now just be aware that they’re minor chords, with a flattened fifth or “b5” ie. the fifth is a semitone lower than it would be in a normal minor chord.

The main lesson to take from this, is just like the Major Scale was formula-based, the Major Key and its chords are too.
So in ANY Major key, the chord based on scale step 1 is Major,  step 2 minor, step 3 minor, and so on as above.  Thus the formula is as follows : 

IMaj     IImin     IIImin      IVMaj      VMaj     VImin     VIIdim

You should practice applying this formula to other Major scales to create Major keys, and make sure you fully understand it.

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Music Theory Part 4 – Relative Major/Minor Scales

Welcome to part 4 in our series on Music Theory.  So far we’ve covered tones and semitones, the major scale and the minor scale.
Today’s post is about relative major and minor scales.

This is a way of grouping scales in pairs of one major and one minor.  Thus we’re left with a pairing of a major scale and its relative minor, or a minor scale and its relative major.  (Depending on which way you look at it, ie. the 2 scales are relatives of each other)

  • To find a major’s relative minor, go to the 6th step of that major scale.  (Which also happens to be the note 3 semitones down from your major root).
  • To find a minor’s relative major. go the the 3rd step of that minor scale.  (Which also happens to be the note 3 semitones up from your minor root)

eg.1 Starting from C Major to find its relative minor : 

I        II        III        IV        V        VI        VII
C       D        E         F         G        A         B

So C major’s relative minor is A minor,  and equally therefore A minor’s relative major is C major, as we’ll see below.

eg.2 Starting from A minor to find its relative major :

I        II        III        IV        V        VI       VII
B        C         D        E        F         G

So A minor’s relative major is C major, and equally therefore C major’s relative minor is A minor, as we’ve already discovered.

So what we’re left with is the following system of pairings, shown in the table below:

Relative Major                                          Relative Minor

C                                                                A
C#/Db                                                        A#/Bb
D                                                                B
D#/Eb                                                        C
E                                                                C#/Db
F                                                                D
F#/Gb                                                        D#/Eb
G                                                               E
G#/Ab                                                        F
A                                                                F#/Gb
A#/Bb                                                        G
B                                                                G#/Ab

Whether you learn this systematically like times tables, or let it assimilate naturally as you gradually learn and improve, or just rely on working a relative out on the spot by moving up or down the right number of semitones or scale steps, doesn’t really matter.  What’s important is that you understand the core of this :

  • Scales are grouped in pairs of one major and one minor
  • The two in each pairing are said to be “relatives” of each other
  • To find a relative minor, go to step 6 of the major scale, or down 3 semitones
  • To find a relative major, go to step 3 of the minor scale, or up 3 semitones

Finally on this subject, let’s just touch on what exactly makes the relatives related, and why that might be useful to us, taking the pairing of C major and A minor as an example again.

C major scale – C  D  E  F  G  A  B

A minor scale – A  B  C  D  E  F  G

The notes in the two scales are the same.  The A minor scale is essentially the C major scale, but starting on A.  Equally, the C major scale is the A minor scale, starting from C.

So all that differentiates between something being “in” C major or being “in” A minor, is whether it is “C” or “A” that is perceived to be the “root” or “tonic”.  A song may have a very minor, sad feel, with heavy emphasis on an A minor chord, so you’d say that is in A minor, rather than C major.  And vice versa.

What’s important to understand, as it’s something that keeps coming up in the study of music theory, is that these two things are just different versions of the same thing.

If you have any questions,  find our teachers on twitter and ask away!

Next time, building chords and understanding “keys”

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