Understanding theory

K

ey signatures are shown at the beginning

of a piece of music and are either a

series of sharps or flats. You will see a key

signature immediately after the clef in a

piece of music, and this saves the composer from

having to add them after each required note. They

explain two things; firstly, the key the piece is in

and secondly, which of the notes you play as either

sharps or flats. The order that sharps and flats are

placed in a key signature will always remain the

same. There are two mnemonics that we can use

to help us remember these orders on a treble clef

stave. For sharps we can use:

Interpret key signatures

Explore the role of key signatures in music, learn why

they are needed and how to read them

“Key signatures

are shown at the

beginning of a piece

of music”

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F

C

A B

G

D E

Father Charles Goes Down And Ends Battles

Battle Ends And Down Goes Charles’ Father

For flats we can use:

So, how do we work out a major key from the

key signature? If there are no sharps or flats, it’s C

major. For sharps, you must look at the last one

in the signature. If you move it one semitone up

it will be the first note and the name of the major

key. The example below is D major.

For flats, you have to remember that F major has

one flat (Bb). For all other key signatures using two

or more flats, the penultimate flat will tell you the

name of the major key.

The penultimate flat in this example is a B. This

key signature is Bb major.

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Last sharp

Changing to minor It’s all relative

The sound of the piece of music will tell you if it is

a major (happy) of minor (sad) key. You can work

out the name of the relative minor key to a major

key by looking at the sixth note of the scale. A

relative minor will have the same key signature

as its major key. This example of C major shows

A as the sixth note, so C major’s relative minor is

A minor.

1s t

6th

B

A

G F

E

D

C

Penultimate flat

Top tip

Accidentals

Don’t think that just because you’re

playing or composing in a specifi

key signature that you need to c

use those sharps and fl

use accidentals to play notes that ats. You can

don’t belong in the signature. An

accidental is a little symbol – either

of a sharp, fl at or natural – that

overrules what the key signature

dictates for the duration

of that bar.