Chord Theory

Notation and chord theory on the fretboard.

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I. The Fret Board The first that you will need to learn is the notes on the fretboard. It is very important to any theory on guitar to know where the notes are on the neck. At first, memorize the notes on the first couple of strings. Then figure out what the notes on the rest of the strings will be. In a pretty short amount of time you should be able to do that. In time you'll develop more of a feel for where the notes fall, without having to think about it, but that's not necessary for chord theory. What you really need to be able to do is to be able to figure out what notes you're playing in a given chord.
e||-F--|-F#-|-G--|-G#-|-A--|
B||-C--|-C#-|-D--|-D#-|-E--|        Note: # = sharp
G||-G#-|-A--|-A#-|-B--|-C--|              b = flat
D||-D#-|-E--|-F--|-F#-|-G--|
A||-A#-|-B--|-C--|-C#-|-D--|-D#-|-E--|-F--|-F#-|-G --|-G#-|-A--| 
E||-F--|-F#-|-G--|-G#-|-A--|-A#-|-B--|-C--|-C#-|-D --|-D#-|-E--|
Notice that there is a full step between all notes except for B and C, and E and F. For the sake of simplicity I have only shown sharps, but it is important to understand where.the flats are. A# (# = sharp) is equal to Bb (b = flat). D# is equal to Eb. B# is equal to C, and Cb is equal to B. Once again, for the purpose of chord theory, it is not necessary to be instantly familiar with every note on the fretboard. What is necessary is to be able to figure out the notes of any given chord that you are playing. II. Keys (the Circle of fifths) The next step in understanding any guitar theory is to understand the circle of fifths. Its importance is that it diagrams several important concepts. First, it is used in determining scales. Second, it is used to determine which chords are in any given key. Third, it is the basis for chord substitutions. To begin with, I'll demonstrate how the circle of fifths is used in a blues progression in G (something that hopefully everyone is familiar with). Twelve bar blues in G begins with 4 bars of G, 2 bars of C, 2 bars of G, one bar of D7, one bar of C, one bar of G, and finally one bar of D7 (as shown below). This progression is also commonly known as
|G   |G   |G   |G   |C   |C   |G   |G   |D7  |C   |G   |D7  |
a I - IV - V progression. If you are not familiar with this progression, learn it. It is one of the most basic building blocks in rock music. Traces of it can be found in everything from Led Zeppelin to Doo-Wop to surf music to Eric Clapton. The next diagram shows the chords that are in the key of G.
I  II  III  IV  V  VI  VII
G   A   B   C   D   E   F#
As you can see, the G is the I, the C is the IV, and the D7 is the V in the I- IV - V progression. Any F chords played in the key of G need to be sharped, otherwise they are considered to be out of key. In the same way, the circle of fifths shows which notes need to sharped or flatted in chord constuction. To form a major chord, the first, third, and fifth notes of the scale need to be played. In the case of Gmajor (or just G as it is commonly called), a G note would be 1, a B note would be 3, and a D note would be 5.
e||---|---|-o-|---|  G  (1)     As you can see, the open G chord
B||---|---|---|---|  B  (3)     is made up entirely of G, B, and D notes
G||---|---|---|---|  G  (1)     (I, 3, and 5).  Note that any G chord
D||---|---|---|---|  D  (5)     requires a 7 note to be played would
A||---|-o-|---|---|  B  (3)     be an F#, not an F.
E||---|---|-o-|---|  G  (1)
For the third part, the Circle of fifths gives an indication of when to play minors, etc. The following chart shows some guidelines. Later on I = major II = minor7 III = minor7 IV = major V = dominant7 VI = minor (known also as the relative minor) VII = diminished I will show some substitution rules for incorporating more unusual chords into a progression. It is important to remember that these rules are only general guidelines. If you look at the chords of some songs that you know, you will probably see that as a general trend, these rules are followed, but on many occasions they aren't. One thing to keep in mind: a chord progression may be in the key of A (A is the I chord) without playing an A chord first. Look at the following example.
  |E   |E   |A   |D   |
This the chord progression in Lola, by the Kinks. In this case, it is in the key of A (A = I, D = IV, E = V). This shows that the first chord played in a progression does not determine the key. Another example is the IIm - V - I chord progression, which is one of the most common in western music. As you can see, it starts on the IIm chord. Since I don't have very good graphics capabilities here, I will represent the circle of fifths in chart form, as would be read clockwise from 12 o'clock. C - no sharps or flats. G - F# D - F#, C# A - F#, C#, G# E - F#, C#, G#, D# B - F#, C#, G#, D#, A# F# (Gb) - F#, C#, G#, D#, A#, E# (F) Db - Bb, Eb, Ab, Db, Gb Ab - Bb, Eb, Ab, Db Eb - Bb, Eb, Ab Bb - Bb, Eb F - Bb Notice the spacing between chords is the same for each key. Here is the example again in the key of G.
I   II   III   IV   V   VI   VII
G   A     B    C    D   E    F#
Notice that there is a whole step between all chords except between III and IV, and between VII and I. This will be true for all keys. That pattern is also the same as that for the major scale. The above diagram shows the notes contained in the G major scale. The VI chord is called the relative minor, because it shares many notes with the tonic (I chord). If C were the tonic, Am would be the relative minor. If you play one after the other, you will notice they sound good together. If something is played in an Am key, you use the exact same chords as if it were being played in the key of C. In this way, you can determine all of the mionr keys as well from the circle of fifths. 3. Chord Construction A chord is a group of three or more different notes played together. Every chord is based on a specific formula which relates back to the major scale after which it is named. As shown earlier, the formula for a major chord is 1 3 5 hence a G major (GM) chord consists of the first, third, and fifth notes of the G major scale, G B D (refer to the circle of fifths chart). **Note the ROOT note is the note after which the chord is named (the 1 note). The formula for a minor chord is 1 b3 5. In the case of a G minor (Gm) the notes would be G Bb D. **Note: a G flat major (Gb) is Gb Bb Db, therefore a Gbm (G flat minor) would be Gb Bbb Db, or Gb A Db. There are many cases where a flatted note has to be flatted again according to the chord formula. In the following diagrams I will show the names, formulas, and fingerings for over 30 of the most common chords. The numbers show where to fret the strings and with which finger. A 1===1 means to barre that number of strings with your index finger. Any notes with a question mark? Underneath are optional (can be muted). Any strings with no note shown below are not to be played. Sharp and flat symbols will come before the note (b3). Shown are the most common barre chord fingerings (all open chords can be derived from the barre chord shapes). Not all chords have the root as the bass note, but most do. 1 = index finger, 2 = ring, 3 = middle, 4 = pinky.
Name: Major          +-+-+-+-+-+      +-+-+-+-+-+      +-+-+-+-+-+
How it's written: M* +-+-+-+-+-+      +-+-+-+-+-+      +-+-+-+-+-+
Formula: 1 3 5       | | | | | |      | | | | | |      | | | | | |
                     +-+-+-+-+-+      +-+-+-+-+-+      +-+-+-+-+-+
                     1=========1      1=========1      | | | 1===1
                     +-+-+-+-+-+      +-+-+-+-+-+      +-+-+-+-+-+
                     | | | 2 | |      | | | | | |      | | | | 2 |
                     +-+-+-+-+-+      +-+-+-+-+-+      +-+-+-+-+-+
                     | 3 4 | | |      | | 3===3 |      | | 3 | | |
                     +-+-+-+-+-+      +-+-+-+-+-+      +-+-+-+-+-+
                     | | | | | |      | | | | | |      | 4 | | | |
                     +-+-+-+-+-+      +-+-+-+-+-+      +-+-+-+-+-+
 
                     1 5 1 3 5 1      5 1 5 1 3 5        1 3 5 1 3
                                      ?         ?
* G major can either be written GM or more commonly just G.
Minor
m                    +-+-+-+-+-+      +-+-+-+-+-+
1 b3 5               +-+-+-+-+-+      +-+-+-+-+-+
                     | | | | | |      | | | | | |
                     +-+-+-+-+-+      +-+-+-+-+-+
                     1=========1      1=========1
                     +-+-+-+-+-+      +-+-+-+-+-+
                     | | | | | |      | | | | 2 |
                     +-+-+-+-+-+      +-+-+-+-+-+
                     | 3 4 | | |      | | 3 4 | |
                     +-+-+-+-+-+      +-+-+-+-+-+
                     | | | | | |      | | | | | |
                     +-+-+-+-+-+      +-+-+-+-+-+
 
                     1 5 1b3 5 1      5 1 5 1b3 5
                                      ?
This is the last standard minor that I will diagram. All chords can be turned into a minor by flatting the 3 note. I will diagram a couple that are not apparent, but the rest are very easy to figure out using this formula.
Fifth
5                    +-+-+-+-+-+      +-+-+-+-+-+
1 5                  +-+-+-+-+-+      +-+-+-+-+-+
                     | | | | | |      | | | | | |
                     +-+-+-+-+-+      +-+-+-+-+-+
                     1 | | | | |      | 1 | | | |
                     +-+-+-+-+-+      +-+-+-+-+-+
                     | | | | | |      | | | | | |
                     +-+-+-+-+-+      +-+-+-+-+-+
                     | 3 4 | | |      | | 3=3 | |
                     +-+-+-+-+-+      +-+-+-+-+-+
                     | | | | | |      | | | | | |
                     +-+-+-+-+-+      +-+-+-+-+-+
 
                     1 5 1              1 5 1

Suspended 2
sus2                 +-+-+-+-+-+      +-+-+-+-+-+
1 2 5                +-+-+-+-+-+      +-+-+-+-+-+
                     | | | | | |      | | | | | |
                     +-+-+-+-+-+      +-+-+-+-+-+
                     1=========1      | | 1=1 | |
                     +-+-+-+-+-+      +-+-+-+-+-+
                     | | | | | |      | | | | 2 |
                     +-+-+-+-+-+      +-+-+-+-+-+
                     | | 3 4 | |      | | | | | |
                     +-+-+-+-+-+      +-+-+-+-+-+
                     | | | | | |      | 3 | | | 4
                     +-+-+-+-+-+      +-+-+-+-+-+
 
                     5 1 5 1 2 5        1 2 5 1 5
                     ?                          ?

7 comments sorted by best / new / date

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    AeolianWolf
    **Note: a G flat major (Gb) is Gb Bb Db, therefore a Gbm (G flat minor) would be Gb Bbb Db, or Gb A Db.
    Gb A Db is NEVER a Gbm chord, even though it sounds like one. a Gbm chord is, as you wrote, Gb Bbb Db. that's my only issue, though. well written.
    gizmodious
    I'd say be less of a stickler. I find that when I get caught up in terminology and theory at some point it makes my guitar playing less enjoyable. Balance Daniel-san.
    mrddrm
    That is still language and terms being used incorrectly. Just because everyone calls a Perfect 5th a power chord doesn't make it so. In a couple more decades it may be completely accepted as a chord, but until then, rules are rules with language. Often, you hear this erroneous term in guitar centric music (such as Jazz and Pop music). I'm very much a stickler with this because I used to call everything that had more than 2 notes a chord because of incorrect guitarists.
    FuruiShin
    I can say even more... wtf people still put here things which are already here in other lessons usually even in better form than this ;]? I mean it sure took you some time and it's great! Somehow that's not everything about this topic here in this lesson altrought it's quite deep.
    Nergal22691
    mrddrm wrote: My only complaint, after a brief look through, is that often roman numerals are written in upper case for major and lower case for minor, because sometimes, the composer DID decide to go against theory and make a III into major, when it should be minor. But I did not have time to read through it in depth. It looks like you cut short on the chord creation, too... what about augmented chords? Diminished? 7th? major7th? etcetera? Technically, suspended and fifth are not chords, so your only true chord is the major. (though yes, suspended and fifths are treated as chords, but only in the guitarist world.)
    The part about suspended chords not necessarily true. Any musician that reads chord charts and follows lead sheets while comping (keyboards, organ, guitar, bass, even accordion and harmonica) will at some point encounter sus chords in the progressions. It is true that when doing harmonic analysis suspensions are considered non-chord tones and are labeled as such but suspended chords are still used by musicians besides guitarists (generally in jazz or pop charts).
    mrddrm
    My only complaint, after a brief look through, is that often roman numerals are written in upper case for major and lower case for minor, because sometimes, the composer DID decide to go against theory and make a III into major, when it should be minor. But I did not have time to read through it in depth. It looks like you cut short on the chord creation, too... what about augmented chords? Diminished? 7th? major7th? etcetera? Technically, suspended and fifth are not chords, so your only true chord is the major. (though yes, suspended and fifths are treated as chords, but only in the guitarist world.)