Music theory, introduction.

Music Theory, introduction.

Today we’re looking at four of the most points of Western musical theory and the way that we can apply them practically. While there are many more aspects of music theory that we won’t dive into today, we do need to understand these four concepts before we can move into the more advanced topics.

To start things off I want to discuss the importance of learning musical theory, many of the greatest musicians of all time did no music theory whatsoever. So why should we learn it?

Understanding music theory makes us musically literate which makes portraying ideas much easier to communicate ideas with other musicians. It also aids our ears, if we understand and can label certain sounds, then we’re more likely to be able to pick out that sound in a musical setting. Ultimately theory is another tool in our musical toolbox and just because we understand the guidelines doesn’t mean that we have to follow them all the time. There’s a reason it’s called musical theory and not the musical law.

I’ve never met a musician who wished that they didn’t know their music theory a bit better, so let’s dive in point number one building major scales.

Introduction to Scales

Our ears have been trained so that music built from the standard major or minor scales sounds to sound the norm.

In the earliest stages of music instruction, we learn that these scales have seven different notes with the eighth note being the same as the first but an octave higher. It’s called an octave because it’s 8 notes from the tonic: A, B, C, D, E, F G, A etc

In order to play a scale which is in the key of c-major on the keyboard, all we need to do is hit all the white notes between one C and the next C.

Going from one piano key to whichever key is higher regardless if its black or white is considered a half-step or semitone and logically if we skip a key and go up by two keys that are called a whole step, or tone.

Let’s analyse the C major scale. When broken down there’s a certain pattern of whole steps and half steps that makes up this major scale that’s what I want you to understand and here’s the practical side of this on guitar. The equivalent of going up by a half step, semitone or one key on the keyboard, is going up one fret on the guitar. Going up two frets is the equivalent of a whole step, tone or two notes on the keyboard.

If you understand this spacing of a major scale, e.g. Tone, Tone, Semi Tone, Tone, Tone, Tone,  I can play this on one string across my instrument. This is crucial because it lays the basic framework for knowing which notes I can play which will sound correct in the key you’re in.

Understanding Key Signatures & the word key.

The term key has multiple meanings in a musical setting, It can refer to the physical keys on a keyboard or it can refer to playing within a certain scale which contains a certain number of sharps, flats or none at all. C Major or A Minor has no sharps or flats.

Circle of Fifths.

Circle of Fifths

Every possible note and there are 12 of them, can have a major scale built from each of these 12 notes. All we need to do is follow that same pattern of half steps and whole steps that we discovered in a C major scale.

Let’s try building a G major scale. If we hit only the white keys again everything lines up perfectly until we come to the note F. This note is too low and it needs to be a half step higher so what can we do here we raise it to the next note instead of an F, it’s now an F-sharp.

Now we know which notes are in our G major scale, alternatively in our F scale we run into some trouble when we hit our note B. This note needs to be lowered so we make it a B flat and now it fits into our pattern of a major scale, Tone Tone, Semi Tone, Tone Tone Tone Tone.

Every major scale we build will follow the same formula we’re just going to need to tweak some notes here and there making them sharp or flat in order to fit the mold.

The good news is I’m going to show you a shortcut so that you can figure out which scale has which sharps and flats using a musical tool called the circle of fifths.

In this circle, we have all possible notes of the western scale available to us. A Bb, B, C, C#, D, Eb, E, F,F#, G#, Ab,

How the Circle of Fifths work.

Starting at “12 o’clock” we have C which as we know has no sharps and no flats. As we travel anti-clockwise around the circle we’re going to add one flat at a time to our scales.

The first key is F major which has one flat, b-flat. The second key is Bb Major, which has two flats etc. You go back to the second to last flat to work out the major key which it is you’re in. So if you had the 2 flats in your key signature e.g: Bb, Eb you’d go straight back to Bb, so therefore your key will be Bb Major. If you have three flats, Bb, Eb, and Ab, your key is now Eb Major.

On the right hand side of the Circle of Fifths, when you’re working out a key signature for sharps, it’s different. We take the last sharp and go up a letter in our musical alphabet and this is how you work out your major key signature for sharps. F# would be the key of G Major, a key signature containing the sharps F# C# would be the key of D Major. F# C# and G# will be A Major.

Relative minor

To work out the relative minor we need to go back 3 notes excluding any sharps or flats and this works regardless of the key signature. If you’re in the key of D major which has 2 sharps, you’ll go back three notes to work out it’s relative minor: D, C, B. Our relative key signature is going to be, B minor. For G Major, the relative is E minor.

The next step is to figure out the order of sharps and the order of flats. To do this we use two nonsense sayings that help us. Remember when adding flats in order for our key signature, we use the saying: Battle Ends And Down Goes Charles’s Father. When adding sharps we reverse this sentence. Father Charles Goes Down And Ends Battle.

When we need to add one flat to our key signature, we look at the first letter of the first word in the same sentence, which is battle. When we add another flat, it will be E flat.


From our Circle of Fifths, we know that the key of F has one flat and which is B flat, which makes sense following our tone, tone, semi-tone, tone, tone, tone, pattern which is the analysis we did earlier. F G Bb, C, D, E, F.

When we need to add two flats to our scale we add the first letter of the second word from our sentence, which means our second key signature now contains two flats, Bb & Eb creating the key of B flat major.


When figuring a key signature which has sharps (#), we take the same sentence but we say it in reverse. Father Charles Goes Down And Ends Battle and the same concept for creating a major scale using our tone tone semi-tone, tone tone tone semitone pattern applies.

If we need three sharps they would be F # C # and G #. This key would be in the key of A Major, remember you take the last sharp which is G Sharp, and go up a letter in the musical alphabet – A B C D E F G.

More info here


Now we know how to spell any major scale using either sharps or flats, if I’m playing a solo or melody and I know that my band is playing in the key of E, I now know which notes I can play that will fit within that key using the Circle of Fifths.

I now know that E has four sharps in it and using my phrase I know that those sharps are F# C# G# and D#. So when I’m shredding away in the key of E, I know the common notes that I can use are e F# G# C# D# and E.

A guitarist thinks of scales as shapes or patterns.

When playing guitar however, we usually think of the scale’s shape rather than what notes we’re playing making the thought process of improvising and playing a melody a lot more fluent.

Fancy booking music theory lessons online?

Music theory courses are available to purchase online and with Bedford Guitar Teacher and it’s a great way to learn music theory and be anywhere in the world.

I use the standard ABRSM Music theory work books produced by Eric Taylor. You’ll need two books. ABRSM Music theory work book 1 (if you’re a beginner, and the A-B Guitar to music theory by Eric Taylor.


ABRSM stands for Associated Board Royal Schools of Music. You can take your exam anywhere in the world as they are an internationally recognised examining body.

To complete grade 8 on any instrument with ABRSM you will need to pass grade five theory. Music theory is also the best way to communicate your musical ideas on paper and in person. It’s a language of it’s own and is also recognised across the world and it really does help to be musically literate.

Let’s make a start.

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