Understanding and Expanding Chords - Guitar Lesson 8
Written by Philip du Toit   
Thursday, 26 November 2009 15:14


Although chord formation was discussed in depth in Lesson 3, we now look at some of the logic on why we play certain chords in certain keys and how to expand them.


In any major key, there are three basic major chords and three basic minor chords that are mostly used in that key.


In the key of C, the tree basic major chords are C,   F  and  G.
Each of these majors has a related minor that can often be interchanged with these majors.



A Related minor is always three halftones (semitones) lower than its related major.

C major’s related minor is A minor (Am).
F major’s related minor is D minor (Dm).
G major’s related minor is E minor (Em).



So what do we have now in the key of C?  We have C, Am, F, Dm, G and Em.


In the key of C, you can build a chord on each note of the scale:


C    Dm    Em    F    G    Am...
1      2         3      4     5      6...



Stop here for a moment.



Play these chords in root form on the guitar.


The complete set of chords in C major thus looks like this:


C    Dm    Em    F     G   Am    Bdim    [C]
1      2         3      4     5      6        7        [1]


These seven chords are called tritones or triads.  Each of them is built on a note of the scale of C major.  This is the building blocks of how to harmonize a piece of music in the key of C.  They are the basic chords used for any tune in C. 



Let’s now take it one step further.  The following pattern emerges:


major    minor    minor    major    major    minor    diminished.
    1          2            3          4           5           6               7            (notes in any scale)     


This is a fixed pattern for all chords in a specific key.  Let’s now take the key of E as an example.  The tritones in E will be:


E    F#m    G#m    A     B    C#m    D#dim    [E]
1       2         3       4     5       6          7          [1]



In harmony, the chords built in any key, can be indicated as follows:


1    2     3      4      5     6      7
I     ii     iii     IV      V     vi     vii


Note that the minors and diminished chords are indicated by lower case, and the majors are indicated by upper case.  In this way, chords can be non-key specific.



See the following sequence:


I     ii    V7    I

In the key of D, this will be D, Em, A7, D
In the key of A, this will be A, Bm, E7, A


What will the same sequence be in F major?



Hover for the answer.




See if you can understand and memorize this principle.




ow view Chordexpansions.pdf in a new window (click).


Look at the top row (horizontal).  This is the tritones as discussed above.  It is written in the chord formulas (as explained in Lesson 3). 


Important!  These are the basic chords used in any Major key.  Guess what chords do you use in a Minor key!?  The same chords as in that minor's related major key!  E.g. if you play in Am, you will use the chords of C major.  The main difference is that you will start and end in Am (the related minor).   One of the other differences is that you will tend to play a major on the third harmony in stead of a minor (in this case E).


Now look at the second row (Exp1).  These are the same chords as in row one, but it is in first expansion mode.  To each of the tritones, another note is added – a seventh.  Note that it is a normal seventh (7) in some cases and a flattened seventh (b7) in some cases. 


Here is the logic:  In the key of C, play all the tritones first (C  Dm  Em  F  G  Am  Bdim).   Now add seventh notes to each chord that are in the key of C.  Relative to the root note of each chord, some sevenths will be flattened sevenths and some will be major sevenths.  So, in row two, we now have:  Cmaj7   Dm7   Em7   Fmaj7   G7   Am7   Bm7b5.  Note that all the seventh notes of each of these chords is a note in the C Major scale.



At this stage, we could tell you that the dim chord and its expansions are rarely used in normal harmonization.  Most important is that you remember where the sevenths are and where the flattened sevenths are:


Imaj7 (normal seventh)
ii7 (flattened seventh)
iii7 (flattened seventh)
IVmaj7 (normal seventh)
V7 (flattened seventh)
vi7 (flattened seventh)


The sevenths and flattened sevens almost correspond to the majors and minors, with one exception, that is the V7.  This is the fifth harmony.  It is called the dominant seventh.  It is often used in harmonization and anticipates going back to the tonic (first harmony).  Try to remember and memorize this sequence.


Now see of you can work out the second row (with the added sevenths) in the key of D (leave out the diminished).  Now, you will use notes in the key of D.



Hover for the answer.




OK, so what are these expansions for?  This is the way you can “color in” your chords and make them sound richer and more jazzy.  You can expand the chords of any song in this way.  Fist determine which harmony it is (e.g. if a Dm is played in the key of F, it’s the sixth harmony), and look on this table (Chordexpansions.pdf) or work out the chord expansion by yourself.  The next step will be to use them in any song and also learn how their inverse forms would look like.  This takes time and practice.



Now look at the third row on Chordexpansions.pdf (Exp2).


Now we are engaging in a little bit more jazzy stuff.  You now build an added ninth note on top of your seventh chords.  This will alter your chords to 9’th and major 9’th chords.  Add a ninth note on top of each of the seventh chords (e.g. Cmaj9 = C  E  G  B  D).  Note that your ninth notes will all be in the key of C.



Visit our GUITAR CHORDS INDEX on how to play the chords.



Try also to do this in other keys (let's say G).


For some, this might become an acquired taste.  But you can teach your ear to appreciate jazz in much the same way as one can learn to appreciate red wine, olives or sushi.


By replacing normal chords with ninth chords (as on this table) you can enrich your harmonies.


f you like this, you can advance to Exp3 and Exp4.


You will see that playing an 11’th or 13’th chord is often appropriate on the fifth harmony (V).  You will also notice that as you expand chords, you can start to drop some of the basic notes.  The eleventh is seldom played in thirteenth chords.  Many of these chords will make more sense on different locations on the guitar neck (different inversions), and played within the context of the harmonic line within a song.



Now let’s put theory to practice.  Play this version of “Oh when the saints” going full circle.  These two files are essentially the same, with the one difference that the first one has a single melody line, and the second one has all the notes.


1. owhensingle.pdf
2. owhen.pdf


Now the most rewarding but difficult part will be to play the song from the correct bass notes. 


If you can work out and master this version of “O when the saints”, you can not only help yourself on the guitar, but you can officially play jazz! 







In the next lesson, we will help you to understand a bit more about harmony and give you some guidelines on changing the harmony of a song or even harmonize a song yourself.




  Advance to:


  Lesson 9 - Harmonic Principles and Progressions



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