In the previous lesson, we saw how sharpened and flattened notes can be represented on the Grand Staff using the “#” and “b” symbols respectively.
When writing music in key signatures other than C Major (which contains no sharps or flats), it is easy to imagine how cluttered the grand staff can become with sharp and flat symbols.
For example, if we wanted to write a piece of music in the key of A Major, which contains the 3 sharp notes F#, C# and G#, we would have to sharpen all the F, C and G notes that are played within that piece of music.
To remedy this problem, we can indicate the key a piece of music is written in by sharpening or flattening all the notes that are altered in that key at the very beginning of the score. This is known as the key signature.
To learn more about how key signatures are derived and how to memorize them, visit the Key Signatures lesson in the Music Theory section.