Numerical Analysis of Chords.
How to figure out chords on the guitar. (Part One)
Playing the guitar is not just about learning basic open-string "cowboy" chords and never expanding on your chord vocabulary. If you limit yourself to only knowing how to play a handful of chords, you are missing out on being able to play hundreds of songs. Mathematically speaking, there are literally thousands of possible chord combinations on the guitar. Do you need to know them all? Absolutely not. However, knowing how to figure out just about any chord structure you come across, will expand your chord vocabulary to being nearly unlimited.
You need to know what makes up a chord.
Taking into consideration that basic open-string chords are structured in the first octave - understanding how you can also add notes from the second octave, will help you learn expanded and double-octave chords. These chords are sometimes referred to as "jazz" chords. They usually include, but are not limited to variations and alterations of 9ths, 11ths and 13ths.
Triads
Basic major and minor chords are the two most popular, basic "triads" in music. However, there are variations on these structures as well. The other four commonly used triads are diminished, augmented, suspended (4th) and suspended 2nd.
Four note chords
Beyond triads are the "four note" chords. These chords include major 7th, minor 7th, major-minor 7th, major 7th-suspended 2nd, major 7th-suspended (4th), Major-minor 7th-augmented, dominant 7th, dominant 7th augmented, dominant 7th-flat 5th, diminished 7th, half-diminished 7th, augmented 7th, dominant 7th suspended (4th), dominant 7th suspended 2nd, major 6th, minor 6th, flat 6th and minor flat 6th. I'll bet you never knew there were so many combinations - and that's just the first octave!
Extended chords
Now, we're getting into what I call "wide" chords. I derived this term many years ago, when a piano teacher friend of mine told me that she sometimes thinks of double-octave chords on the piano as being stretched out or "wide". This is easily understood by how many notes are being played in the extensions of these types of chords.
However, the same does not always apply to the guitar. The guitar only has six strings, so this can be a significant limitation as to how many total notes can be played in any given chord, extended or otherwise.
In the image below, you can see the entire fretboard of the guitar outlined in Roman numerical placements. Think of it as a layer on top of the fretboard that indicates the "static" positions of all of the structures of notes in chords. Whichever Roman numeral is needed to make a specific type of chord, you can find several combinations of that chord structure through this analysis. Some of these structures might look familiar to you.
Chord structures
Triads:
Major = I - III - V
Minor = I - iii - V
Diminished (b5th) = I - iii - v°
Augmented (#5th) = I - III - #V
Suspended (4th)= I - IV - V
Suspended 2nd = I - II - V
The next section will include a list of the "Four note" chord structures mentioned earlier in this article. That article will be posted in the upcoming "Part Two" of this series.