One of the biggest keys to writing great songs and killer solos for guitar is to have a solid understanding of music guitar theory.
When you learn the basics of how to create chords and how to fit them together, you’ll have the information you need to begin writing your own music and putting together solos and lead lines that sound great and fit in well with the character and mood of your song.
If you’re improvising, you’ll have a better sense of which notes will sound good and which ones won’t.
It’s also a big help in learning songs by ear; when you know the most common chord progressions, you have a head start in figuring out where a song is going next.
In this guide to learning music theory for guitar, I want to cover the basics of finding the notes in a major and minor scale, constructing major and minor chords, and how to create chord progressions that flow together.
Theory of Major scales on Guitar
The simplest scale to start with is the C major scale. This scale contains the notes C D E F G A B. There are no sharps or flats in the C major scale. It can be played on guitar like this:
e|--------------------------------------------------|
B|--------------------------------------------------|
G|-------------------2--4--5------------------------|
D|----------2--3--5---------------------------------|
A|----3--5------------------------------------------|
E|--------------------------------------------------|
Major scales can start on any note. Every major scale follows a set pattern. We’ll use the C major scale as our example. The root note is the note for which the scale is named, in this case, C. The next note, D is 2 semi-tones or one full tone ( think of it as two frets on the guitar ) higher than the root. From D to E is also one full tone. There is just a semi-tone from E to F. From F to G and G to A and A to B there is again a full tone difference. Finally, from B to C there is just a semi-tone difference.
So, to recap, you can find the notes of any major scale by choosing the root note and then following the pattern of tone, tone, semi-tone, tone, tone, tone, semi-tone.
The Minor Scale
A minor scale is slightly different from a major one in that a minor scale, the third, 6th and 7th notes of the scale are one semi-tone lower than in a major scale. A C minor scale includes the notes C D Eb F G Ab Bb. This changes your pattern to tone, semi-tone, tone, tone, semi-tone,tone, tone.
A C minor scale can be played like this:
e|--------------------------------------------------|
B|--------------------------------------------------|
G|--------------------1--3--5-----------------------|
D|-----------1--3--5--------------------------------|
A|----3--5------------------------------------------|
E|--------------------------------------------------|
In the key of C, however, we don’t have the notes Eb, Ab or Bb. So, to play a minor scale in the key of C, we use the notes of what is called the relative minor scale of C. A relative minor scale begins on the 6th note of the major scale of the key in which you’re playing. An A minor scale is made up of the notes A B C D E F and G. The pattern is the same as for the C minor scale, but now all the notes are in the key of C.
This is the A minor scale:
e|--------------------------------------------------|
B|--------------------------------------------------|
G|-------------------------2------------------------|
D|----------------2--3--5---------------------------|
A|-------2--3--5------------------------------------|
E|----5---------------------------------------------|
Each note in a scale is given a Roman numeral based on it’s relationship to the root. In our example, C, the root, is given the number one (I). D is two (II), E is III and so on.
There are a wide variety of scales that can be played on the guitar, many of which are beyond the scope of this article, but there is one more scale I’d like to talk about since it is so widely used, particularly for playing solos or lead guitar parts. It is called the pentatonic scale.
Major and Minor Pentatonic
A pentatonic scale is a scale made up of 5 notes. There are both major and minor pentatonic scales. A major pentatonic scale contains the I, II, III, V and VI notes of a major scale. Thus a C major pentatonic scale is made up of C, D, E, G and A.
A minor pentatonic scale, on the other hand, contains the I, III, IV, V and VII notes of the relative minor scale for the key in which you’re playing. Again, in the key of C, the relative minor scale starts on A. The A minor pentatonic scale contains the notes A, C, D, E, G
Here’s the tab:
C major pentatonic:
e|--------------------------------------------------|
B|--------------------------------------------------|
G|-----------------2--------------------------------|
D|-----------2--5-----------------------------------|
A|----3--5------------------------------------------|
E|--------------------------------------------------|
A minor pentatonic:
e|--------------------------------------------------|
B|--------------------------------------------------|
G|--------------------------------------------------|
D|-------------2--5---------------------------------|
A|-------3--5---------------------------------------|
E|----5---------------------------------------------|
Creating Major and Minor Chords
Now that you know how to construct scales, the next logical step is to create chords. Major chords contain the I, III, and V notes of the scale. So a C major chord is comprised of the notes C, E and G. You can add the root note an octave higher if you like to give the chord a fuller sound.
A minor chord is comprised of the I, III and V notes of the minor scale, so a C minor chord (usually written as Cm) is made of the notes C,Eb and G.
There is a tremendous array of chords, using various notes of the major and minor scales, but for now we’re going to stick with just the major and minor chords as we move on to chords progressions.
Chord Progressions
The type of chord progressions you can create is limited only by your imagination, but I want to talk briefly about some of the most common patterns. Probably the most common progression you’ll find is the I, IV, V progression. This progression is used in thousands of tunes. A I, IV, V progression in the key of C contains the major chords of C, F and G. Play through the progression as follows to get a sense of the sound:
C F G C
e|----0----1----2----0------------------------------|
B|----1----1----0----1------------------------------|
G|----0----2----0----0------------------------------|
D|----2----3----0----2------------------------------|
A|----3---------2----3------------------------------|
E|----x---------3----x------------------------------|
You’ll notice that the V chord (G) resolves nicely to the root chord (C). The progression sounds complete, as if the song or phrase has come to an end. A large number of songs finish with a V-I progression for this reason. The IV-I progression is another common way to complete a song or phrase. Think of the “A-men” closing of a hymn. This is the sound of a IV-I progression.
The Beatles “Twist and Shout” is a great example of the I, IV, V progression and you can find the chords and lyrics at
http://www.ultimate-guitar.com/tabs/b/beatles/twist_and_shout_ver2_crd.htm
This version is in the key of D, so the I, IV and V chords are D, G and A.
In addition to the I,IV and V chords, there are 3 minor chords in each key. They are the IIm, IIIm and VIm. In the key of C these chords are Dm, Em and Am. The IIm is the relative minor of the IV chord and can be used in place of the IV chord in a progression. The VIm is the realtive minor of the I chord and can be used in it’s place, though it wouldn’t sound right in the final bar of a song or phrase. The IIIm is not used as often, but is the relative minor of the V chord.
As you begin to write your own material, feel free to experiment with these chords and sequences. Once you know the basics, you can branch out and find new ways of combining them to achieve the sounds you want. You’ll also begin to recognize certain progressions in the music you listen to and will improve your sense of what works in a song and what doesn’t.
Congrats on getting through this guide, you’ve learned all about getting Major, Minor and Pentatonic Scales built, Chords and Chord progressions. That’s enough theory for now, it’s time to head back to the home page and carry on with the how to play guitar guide.
