This is part of a tutorial on working out guitar chord fingerings from first principles that used to appear across several pages on my old web site. This post will teach you the bits of music theory you’ll need to understand the rest of the tutorial. It does not, however, teach you to read music score — but I strongly recommend you learn to do that after you’ve finished this series. See all the parts of the tutorial.

If you are using a screen reader, you should set it to expand abbreviations to get it to read the note names correctly.

We’ll start from the beginning—skip the bits you don’t need. It would help to know your way around a piano keyboard for this bit, although no playing ability is needed. The white note immediately to the left of any group of two (rather than three) black notes is C, and B is the white note to its left.

Western music is built around the basic building block of the octave, which is split into twelve semitones, each of which is the gap between each adjacent key on the piano (black and white), and each adjacent fret on the guitar. Each octave represents a doubling of frequency. The same note in different octaves has a characteristic sound or pitch that makes it “sound the same”.

The notes have names—the picture below shows just over a complete octave, starting on C:

The “#” sign is a sharp, and means the note is a semitone above the letter given, so G# is a semitone above G. The “b” sign is a flat, and means the note is a semitone below the letter given: Bb is a semitone below B. Flats and sharps in written music are called accidentals when they are modifying a note away from what the key signature (see below) would dictate; we’ll call them modifiers anywhere else. There is also a natural sign to denote the lack of a sharp or flat, which looks like the sharp with the side, top-right and bottom-left protrusions removed:

The “black notes” on the keyboard have two names, like G# or Ab. These are called enharmonic equivalents or spellings, and on instruments that have fixed notes (keyboards, fretted instruments) these are exactly the same note. Really advanced violinists, for example, may play them slightly differently, but that’s beyond the scope of this tutorial.

Contrary to popular opinion, B#, Cb, E# and Fb do exist, and are equivalent to C, B, F and E respectively, as you would expect. On the piano, these are white notes, and beginners’ guides shy away from giving them these alternative names. You won’t come across these very often, as they only appear in the six- and seven-modifier key signatures (see below) or in more complex pieces in simpler keys. See the next post if you’re interested in finding out more.

Self test question 1

What note is six semitones higher than D?

Reveal…

G# or Ab. We can count up: (D)-D#-E-F-F#-G-G#, or (D)-Eb-E-F-Gb-G-Ab.

Self test question 2

What note is five semitones lower than Eb?

Reveal…

A# or Bb. Counting down: (Eb)-D-Db-C-B-Bb, or (Eb)-D-C#-C-B-A#.

Intervals

There are common names for multiple semitone gaps, or intervals. These are shown below. You won’t need to remember all of these, but as I introduce them in later sections, come back and refer to this table. Once you learn about scales, it’ll become clear why the names and numbers of semitones don’t seem to match up!

Self test question 3

With a root note of B, what is the sixth?

Reveal…

G#. The sixth is nine semitones up: (B)-C-C#-D-D#-E-F-F#-G-G#.

Self test question 4

If the fourth is D, what is the dominant seventh?

Reveal…

G. You can either work out that the root is A (down five semitones) then go up ten semitones to the dominant seventh; or you can go directly up five semitones from D (from five to ten above the root).

Scales

There are several scales—sequences of notes—based on these intervals. The table below shows three important scales as semitone interval sequences and the corresponding notes in the key of C — chosen because the major scale has no modifiers, and consists solely of white notes on the keyboard.

Refer to the interval table above, and notice how the interval names match the position in the sequence (third, fourth, fifth etc.).

There is also the melodic minor, which is different depending on whether you are ascending or descending. I don’t intend to cover that here. The harmonic minor is the more important one in this tutorial.

Self test question 5

What notes are in the scale of D major?

Reveal…

Semitone interval: 0  2  4  5  7  9  11 12
Note:              D  E  F# G  A  B  C# D

Self test question 6

What notes are in the scale of Bb minor (harmonic)?

Reveal…

Semitone interval: 0  2  3  5  7  8  11 12
Note:              Bb C  Db Eb F  Gb A  Bb

Keys and key signatures

The key of a piece of music defines the “base” note and the feel of the piece (major or minor). For example, if a piece is based around the scale of E major, it is said to be “in” E major, or just E for short. The key signature at the beginning of the written music score is a shortcut to writing accidentals throughout the piece.

For example, referring to the above tables, the scale of E major is made up of:

E-F#-G#-A-B-C#-D#-E

So to play a piece based around the scale of E major, we need to use these notes exclusively, unless the music intentionally departs from the basic scale to achieve a particular sound. The key signature of E major is therefore four sharps (F#, C#, G# and D#). The table below shows the key signatures for the various major and minor (m) keys:

Music score writes the key signature at the beginning of each line, to establish the default modifiers for each line. For example, here’s a piece in Eb major, which has three flats:

A flat is shown on the B, E and A lines. Don’t worry if this is all Greek to you, but I do recommend you learn to read music score separately from this tutorial.

Here endeth today’s lesson. [Posts in this tutorial]