Key Signatures

Most people first encounter key signatures in the form of the circle of fifths, a clock of letters they are told to memorize – not an easy feat considering there are 30 different key signatures. Through this lesson I will introduce and explain key signatures and, through using mnemonics, introduce an easy way to work them out.

Key signatures?

The key signature is shown on the stave just after the clef but before the time signature. The key signature is shown as sharps or flats on certain lines or spaces telling the performer to play that note one semitones higher for a sharp or a semitone lower for a flat:

Example 1

In the above example, there is a whole note on the line representing an F so the performer would play the first fret on the high E (first) string but the key signature tells the performer to play every F as F# so the second fret on that string would be played instead.

As the name suggests the key signature is an indication of the key the piece is written in, with the sharps or flats shown in the key signature being present in a certain key. The number of sharps or flats present in the key signature relates directly to a major scale.

Building Major Scales with Sharps

Major scales are built using a formula of tones and semitones – a “tone” being two frets distance from a note and a “semitone” being one. Below is the formula for constructing a major scale:

Example 2

When using this formula to work out a C major scale we get all natural notes, meaning there are no flats or sharps:

Example 3

If we then take the fifth note from the C major scale, which is G, and using the formula construct a G major scale we get our first sharp:

Example 4

If we continue to build major scales this way a pattern emerges in the way sharps build through the different keys:

Example 5

The fifth note in a major scale is the new key and the seventh note is the new sharp. The number of sharps in the key signature is directly linked with the number of sharps in a major key, the example below would be in the key of A major, the key signature shows the three sharps in A major F#, C# and G#:

Example 6

Building Major Scales with Flats

The theory is much the same as with sharps except the next scale comes from the fourth degree rather than the fifth. If we go back to our C major scale but take the Fourth note which in this case is an F then using the formula Construct a F major scale we end up with:

Example 7

Bb is used rather than A# because this maintains that each letter name is present only once in the scale. If we continue to build in the same way we did with the sharp keys, a pattern emerges with the flats:

Example 8

As shown above, the fourth note is not only the new key but also the new flat. As demonstrated with the sharps the number of flats in a key signature directly relates with the number of flats in a key, the key signature below has three flats Bb, Eb and Ab so is in the key of Eb major:

Example 9

So far we have covered how to work out 15 different key signatures 7 sharps and 7 flats not forgetting C major, which has neither.

Through using mnemonics, the process of working out what key is represented by a key signature and what notes are sharpened or flattened becomes easy. Just follow the steps below:

How Many Sharps?

  • Count down this mnemonic till you get to the key you want:

Go Down And Eat Bread Father Christmas

  • E.g. E is the forth word so E major has four sharps.

What Sharps?

  • Bring Farther and Christmas to the front of the mnemonic:

Father Christmas Go Down And Eat Bread

  • Count up by the number of sharps
  • e.g. for E major count four
  • This gives you Farther Christmas Go Down

E Major = 4 sharps F#, C#, G# and D#

How Many Flats?

  • Count down this mnemonic till you get to the key you want:

Fred Blogs Eats All Dogs Get Cracking

  • E.g. E is the third word so E flat has three flats.

What Flats?

Bring Fred to the back of the mnemonic:

Blogs Eats All Dogs Get Cracking Fred

  • Count up by the number of flats
  • e.g. for E flat count three
  • This gives you Blogs Eats All

E Flat = 3 Flats Bb, Eb and Ab

Relative Minor

Every major scale has a relative minor scale that shares its key signature. A relative minor scale is built from the sixth degree of its relative major scale, for example below is C major and its relative minor:

Example 10

Relative minors are easy to work out on the fret board, simply put your fourth finger on the Major scale root note for example A fifth fret then place your third finger fourth fret, second finger third then your first finger in the second fret. The note your first finger is on is the relative minor (F#):

Example 11

This now makes the subject more complex if we are faced with this key signature:

Example 12

How do we know if it is D major or Bm?

This can be achieved through listening to the piece and seeing if it has a major or minor key center. Try listening to the two examples below one of the chord progressions is in the key of E minor and the other G major both would have a key signature of one sharp.

Example 1 clearly has a major key center with example two having a minor key center. If the music is in the form of a score or chord chart simply look at the first and last chord if they are minor the piece is in a minor key if they are major it’s a major key.

Here are two PDF’s one for the mnemonics, the second containing a list of key signatures and relative minors, once you think you have got it try this Java game to test your knowledge.