What is a Key Signature?
Following on from last lesson on The major scale, each scale represents a key. The scale of D major is in the key of D major. The scale of G major is in the key of G Major. Easy right?
The D major scale has the notes D-E-F♯-G-A-B-C♯-D in it. This means that if a piece is in the key of D major it mainly uses the notes of the D major scale. (There are some exceptions to this rule, however you won’t need to know them until grade 6-8).
Consequently, if a piece is in D major everytime a F♯ or a C♯ is played there will need to be an accidental present. This can get quite confusing when there is constant accidentals. Therefore you have something called a key signature.
What is a Key Signature?
So what is a key signature?
A key signature goes after the clef symbol, but before the time signature. It looks like this:
Every note in the key that is sharpened or flattened will have an accidental on it’s relevant line.
The key signature above is of D Major. As you know, the D Major scale has a F♯ and a C♯, and if you look at the key signature above it has a ♯ symbol on F and C.
Effects of a Key Signature
Whenever a note is played that has an accidental next to it in the key signature, it will automatically have the accidental in the key signature applied to the note.
Therefore, if we look at the key signature of D Major again:
The sharp symbol is on the F and C line. Therefore if we have a D major key signature at the start of the music, every time a C or an F is played it will be automatically sharpened, as there is a sharp symbol on the C and F line.
This also means, that if you know what key has a C♯ and F♯ in it, then you will immediately know what key the piece is in just by looking at the key signature.
Key Signatures for Grade 1
There are four key signatures you need to know about for grade 1:
The C Major scale has no sharps or flats, so therefore the key signature likewise has no sharps or flats.
The G Major scale has one sharp: F♯, so the key signature only has one sharp on the F line.
The D Major scale has an F♯ and C♯, so the key signature has two sharps on the F and C line.
The F Major key signature only has a B♭, and so the key signature has one flat on the B line.
It is important to remember what lines the sharps and flats go. You will need to know how to write each key signature for the grade 1 exam.
Spending a bit of extra time now memorizing the key signatures will also be extremely helpful in the future.