Guitar Chords Theory
Guitar chords and keys
Every song we play on guitar is in a key. A key is just a matrix if you like, in which there is a logical order of scale and chords. If this is not making any sense, refer to my other hubs on music theory - basically every key has a major scale containing 7 different notes, and seven different chords, each chord is based on the bass note of the major scale that it derives from.
My other hub Guitar Chords and scales in E might help with the theory involved. Another hub on this subject is Guitar Chords - Rhythm Guitar.
The chord diagrams below show the chords for three different keys that are guitar-friendly - E, A and D. Now here's the clever bit:
- The first set of chords is root 6, that is, the root note is on string 6, but after 4 chords the root note transfers over to string 5. This means that you can play the sequence of chords without running out of space on the neck. These are all the chords in the key of E, all the diatonic chords with added 7ths. Why add 7ths? - because it makes the harmony sound more interesting and sophisticated. We like sophisticated.
- Next we have all the chords for the key of A. Note that the pattern of chords is the same, major, two minors, two majors, minor, m7b5 - this pattern is identical for every major key.
- Finally, all the chords in the key of D, with a root 4 bass. This time the whole sequence stays on the same set of strings, because there is nowhere else to go! Check your medical insurance before going for the last D maj7 chord.
Chord pictures info
The six vertical lines are the strings - fret position is given as a number on the left. The loop sign means it's a barre chord, where you flatten one finger over several strings. For the key of E examples,we are avoiding a barre on the first two minor chords, and using thumb over the neck to play notes on string 6 - this is a very useful technique if you want to avoid strain on your left hand.
Harmonised scale chords
Every chord in these sequences has a number, in Roman numerals. Chords I, IV and V are the major chords, and most simple songs use just these three chords. Chords ii, iii, vi are the minor chords.
Chord vii is rarely found outside jazz, Brazilian and classical music but in those genres it is fairly common.
For all other keys, you can just move the whole pattern of chords up the neck. For key of F:
Take the set of chords in E and just move them all up one fret (E to F is one fret)
For key of Bb - same thing, using the chords in A but one fret higher (A to Bb is one fret)
If you have any questions about this, just use the comments box below.
Chords in practice
If you learn these sets of chords, there are several advantages.
- You will understand the guitar fretboard much better
- You should be able to learn songs much more easily, because you will be able to predict the next chord in any song
- Chord arpeggios can be derived from each chord shape - these can be used when improvising, playing lead guitar
- If you play piano or keyboard, you can apply all this theory to playing songs
- A good way to explore piano is to try to play songs that you have already memorised on guitar.