A key signature is a collection of every accidental found in a scale.
To demonstrate this, we will use the key of C Minor, which has three flats.
Instead of writing a flat next to every E, A, and B; we can simply add a key signature to the beginning of the measure.
Instead of writing a flat next to every E, A, and B; we can simply add a key signature to the beginning of the bar.
Next, let's examine Db Major, which has five flats.
Again, a key signature can be used instead of writing each accidental.
As you may have noticed, the flats are arranged in a special order.
Bb is first, followed by Eb, Ab, Db, and Gb.
Next comes Cb and finally Fb.
You can remember this order by using the following saying: “Battle Ends And Down Goes Charles' Father”.
Key signatures can also comprise sharps.
Let's try A Major, which has three sharps.
The C#, F#, and G# move into the key signature.
Finally, let's try E Major, with four sharps
The F#, G#, C#, and D# move into the key signature.
Sharps are arranged in the opposite order of flats.
F# comes first, followed by C#, G#, and D#.
Next comes A#, E#, and finally B#.
You can remember this order by using the following saying: “Father Charles Goes Down And Ends Battle”.
Use this chart to reference key signatures for both treble and bass clefs.