The first step in understanding music theory as it relates to the guitar is to learn the note names. This is a relatively straightforward process and will lay the foundation for learning scales, chords and arpeggios.
Notes belong in one of two categories; natural and accidental. There are seven natural notes and five accidental notes for a total of twelve notes.
The first thing you’ll want to do is memorize the six-string names. If you aren’t familiar with that yet, this video will sort you out. Note that the first and sixth strings are both called E. Feel free to come up with phrases using the order of strings in either direction if you want. In my experience, however, it’s just as easy to memorize the letter of each string and be done with it.
The Musical Alphabet
The musical alphabet contains seven letters: A-B-C-D-E-F-G. These are the natural notes. In order to learn these, you’ll need to understand how the intervallic structure of the musical alphabet works and apply that to the fretboard.
The distance between most natural notes is a whole step (whole tone), which translates into two frets on the guitar. The notes B-C and E-F are the exceptions, being a half step (semitone) apart.
Fig. 2 illustrates this on the A string. The starting point is an open string, which is counted as a fret, therefore A and B are a whole tone apart. In essence, all you need do now is remember the intervallic distance between the natural notes and you will be able to figure out all the note names on the other strings.
Filling In the Gaps
Up until this point, we’ve been concentrating on only the natural notes. So, what about the notes in between? These are called accidentals, a term used for notes that are either sharp (#) or flat (b).
Accidentals are simply alterations of natural notes to either a higher (sharp) or lower (flat) pitch. A sharp raises the pitch of a note by a semitone, whilst a flat lowers the pitch of a note by a semitone.
A sharp and flat note can be the same pitch called by different names e.g. A# and Bb. These are referred to as enharmonic equivalents.
After learning all the notes on each string it’s important to maintain one’s knowledge. The most effective way of doing this is to incorporate note naming into all your practice sessions. When you fret up a chord, name all the notes in that chord. As you play a scale, name each note as you play it. Eventually, you’ll know the fretboard so well, it’ll become second nature and you’ll never have to think about it ever again.