Major/Minor/Diminished
Chord Theory
Chords are the basis of all Western music. They are absolutely crucial to the guitar
and to rock music, and an understanding of chords will improve your understanding of the guitar
and music immensely. This page is designed to help you with the music theory behind chords,
so sit back and prepare to learn more about your instrument in the next ten minutes
than you have in the past month. Before you begin, check out my page on
intervals because this information will be used here.
On this page I will discuss the basics of scales because scales are
important for chord formation, but I will not cover them in depth
because I have a full page on scales.
The figure below shows the twelve notes of the chromatic scale. These are
the only notes used in Western music. Notes such as D# and Eb represent the
same pitch and are called enharmonic equivalents. Different enharmonic equivalents
are used in different scales; the sharp is used for sharp keys
(e.g. F# major), and the flat is used in flat keys (Ab major).
The interval between each of the notes shown above (G and G#, for example) is one half step.
Each fret on your guitar is equivalent to one
half step; twelve half steps make an octave. As you learned in my page on
intervals, two frets (two half steps) make a
whole step. The distance between G and A is a whole step.
As a framework for studying major/minor/diminished chords, I will use
the major scale. The major scale is made up of
the following pattern of whole and half steps:
The notes of the scale are referred to as "root" (or "tonic"), "second,"
"third," "fourth," etc., as shown on the diagram below.
This will be very important when we start constructing chords in the next
several pages. Note that when we say "D is the fourth of A," you count
A as 1, B as 2, C# as 3, and D as 4.
All basic chords you play are made up of three pitches: the root, third, and fifth.
Variations on the theme will be discussed on other pages, but all major, minor,
and diminished chords contain these three notes. If you look at the diagram and try
to build a chord on the note A, you pick out the first (or root), third,
and fifth notes of the scale: A-C#-E. This is shown in the diagram below:
To build a chord on the note B, pick out the root, third, and fifth starting
with B, and you get B-D-F#:
But why is the A a major chord, and why is the B a minor chord?
This comes about because of the pattern of half and whole steps in the scale. Whether
a chord is major or minor depends on the interval, or musical distance, between
the root and third, and the root and fifth. Check out my page on
intervals for more information on them.
The major chord
contains four half steps between the root and the third
(a major third),
and seven half steps between the root and fifth (a
perfect fifth). The major chord follows
the pattern 1-3-5.
The minor chord
contains three half steps between the root and third
(a minor third),
and the same perfect fifth
between the root and fifth. The minor chord follows the pattern 1-m3-5.
If you try to build a chord on the G#, the three pitches are G#-B-D.
The interval between G# and B is a minor third, but the
interval between G# and D is not a perfect fifth (seven half steps), it is
six half steps. This interval is called a diminished fifth, and is a rather unstable
interval. This is why this G# chord is called a diminished chord: it contains
a diminished fifth instead of a perfect fifth.
The diminished chord
contains three half steps between the root and third
(a minor third),
and six half steps between the root and fifth
(a diminished fifth). The diminished chord
follows the pattern 1-m3-d5.
The G#º chord and C#º chord shown below are played just like
barre chords, and can be moved
to whichever fret is necessary. Simply notice the bass note of the G#º is on the sixth
string and the bass note of the C#º is on the fifth string. For more information
on barre chord theory, click here.
As you may recall from the chord-leading lesson, diminished chords
pull strongly toward the major chord a half step higher, so the G#º pulls toward A and C#º pulls
toward D. These chords are not frequently used in popular music, so it is not imperative that
you know how to play them, but if you ever come across one you will know what you are
dealing with.
This concludes the lesson on major/minor/diminished chords. Knowing the theory behind these
chords is a very valuable skill which can be applied to songwriting, figuring out songs, etc.
Study this lesson and the others in this series, and it will make you a better, more
knowledgeable guitarist. I suggest moving on to my discussion of
chords in major keys to complete your understanding of chords
in keys. Enjoy!
Back to Dansm's Guitar Chord Theory
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© 1997 Daniel E. Smith.