What is a key?
If a piece of music uses notes from one of these scales then we’d say it is in that ‘key’.
For example, if a piece of music uses only notes in G major scale then it would be in the key of G major.
Or, if a piece of music uses only notes in F major scale then it would be in the key of F major etc.
The example below is in the key of G major as it uses only the notes from that scale.
However, to save us from having to add all the sharps or flats each and every time when we’re playing in a given key, we use a key signature at the beginning of the music to make it easier to read.
The same melody would look like this with a key signature:
We place a sharp sign on the F
Even the F that is in the first space of the stave.
If the piece was in D major it would have an F sharp (F#) and a C sharp (C#) as its key signature because D major has two sharps.
For example, this piece in D major without a key signature:
But with a key signature it becomes this:
Another example of a piece in F major without a key signature:
But with a key signature it looks like this:
A piece in C major obviously doesn’t have any sharps or flats in its key signature as there aren’t any black notes in C major scale.
The Order and Positions Of The Key Signatures
It’s important to always put the key signature in the right place.
For example in the treble clef, F sharp (F#) is always on the 5th line of the stave but in the bass clef it’s on the 4th line.
Here are the three key signatures in both clefs.
Hopefully, that helps you make a bit more sense of key signatures. I’ll be adding to this post soon going over the other key signatures plus the different clefs like the alto and tenor clef.
In the mean time, I recommend making some flashcards to help you memorise them.