Musical Keys & Key Signatures? Using the Fretboard As Music Theory!

Are you struggling to understand Key signatures? This is a subject that is overcomplicated and can be demonstrated much easier than when I first learned it!

What are key signatures? In music theory, a key signature is simply a group of notes that form the scale of the composition (the track), which is being played. By knowing the key we can work out all the underlying theory so that we can play along with the song in question. Using the guitar we can work out all the underlying Notes and chords just by knowing the key signature!

In this article, we will look into the key signatures in more detail… So let us jump right in!

1. What are Key Signatures?

Music key is most certainly a crucial knowledge if you wish to improve and progress as a musician or a guitarist.

Keys simply tell you which chord and scale to play.

In the simplest term, a key is a group of notes or pitches, featuring a tonic note as its finishing or focal point. A tonic note of a key also corresponds to its scales or chords and at the same time identifies the key. For example, a song played in the key of A minor will use the notes in the A minor scale.

There are 12 minor and major keys in total, corresponding to the scales.

2. Why are Keys Important?

A bit more familiar to the untrained ears as many a time have you probably heard musicians telling each other the key of a song. This knowledge is crucial in the way that it is the means of communication for musicians. Similar to mathematics, music, too, is a universal language.

Knowing which key a song is in allows you to identify and play the correct scales of the songs. This is most useful in jamming with friends, in a group, or in case musicians need to write songs and work with each other.

3. Identifying Keys

The first thing you need to do as a musician is to identify the key of the song that you are playing.

Luckily, this can be done quite easily by following this FIVE step process:

  1. Listen to the song you are playing
  2. Identify the pitch
  3. Match the pitch to the note on the fretboard
  4. identify whether it is major or minor sounding
  5. construct the scale

If you want to more about this in more detail then click the link here… Find the Key of Any Song!Opens in a new tab.

4. Constructing Keys

A key is usually determined by the root note and then a sequence of chords that make the song.

For every key signature, there are major and minor scales that can be played over that sequence of chords.

If it sounds happy then it is Major, and if it sounds sad then it is Minor.

Once you have identified the pitch (A A# B C C# D D# E F F# G G#) and the mood (major/minor), you can then lean forward to construct the scale.

5. Circle of Fifths

If you are playing around with a song and you identify the pitch that sounds nice though the whole song this is usually the Keynote which forms the basis of our key signature.

Next, we need to identify whether it is a major or minor sound.

Then put the two together we have our key signature!

We then use the circle of fifths cart to construct our scale.

Circle of fifths

circle of fifths

The circle of fifths helps us construct our scale. The idea here is that we need to find the major variant of our key signature.

Transposing Major Keys

If the sound is major then the good news is our job is done.

For example, by going through the process identified in section 3 (identifying the key) we identify that the note which sounds good throughout the whole song is the A note.

After, listening to the song and becoming familiar with it we identify it as being happy and so we conclude the key is A Major.

We can now construct our scale by using the CAGED system Process so we move on to Section 6 of this article.

Transposing Minor Keys

If we identify that the sound is minor we then need to use the circle of fifths to convert the minor into major.

This is because major and minor are both within the same family. They share the same key, the only difference is, is the root note which changes the sound from happy to sad.

So for example, if you identify the song as A minor, you will then want to play C major (demonstrated below…).

6. Guitar Theory VS. Music theory

The way guitar theory works is that we transpose any keys from minor into major or keep them as major if already major. As seen above.

But, we only transpose them into major so that we can easily find the correct shape to play (as seen in section 6).

Meaning, we should not identify the key as what it has been transposed into.

So, for example, A minor is always A minor. So we can identify it as sounding like a minor scale. But, we look for the major equivalent so we know the shape which we wish to play.

Learn more about guitar theory Vs music theoryOpens in a new tab. here…

To note: we always transpose to major so that we don’t need to learn the same shape twice.

7. Major Keys

Once you have transposed your key into the major variant we can then know what shape we must play seen below…

A Major

A# Major

B Major

C Major

C# Major

D Major

D# Major

E Major

F Major

F# Major

G Major

G# Major


By using the circle of fifth you can then find your keg signature without needed to mathematically calculate intervals. then apply those intervals to the fretboard.

This is a very difficult and timely skill to build.

SO instead we use the circle of fifths to convert the minor to major and then use the shape of the CAGED system to know the scale.

Thus, cutting out a massive part of the process. Making improvising more practical.

Rich Wilde Music

My name is Richard Wilde and go by @richwildemusic on all major social channels. I am an artist, guitar player, and producer. I have been playing guitar for over 15 years and have come to learn the "tips" and "tricks" to enhance guitar playing, recording guitar, setting up guitar, and overall get that professional sound.

Leave a Reply

Your email address will not be published. Required fields are marked *

Recent Posts

link to Buckethead


Buckethead is a well-known guitarist who is widely recognized as one of the most talented and inventive musicians of his age. Over the course of his career, he has released over 300 studio albums and...