Key Signatures

The key in which a piece of music is written determines which pitch is tonic (i.e., the pitch that sounds central or like “home”). In the previous chapter on scales, the tonic of each example was C. The tonic of this example is D, and the major scale is written out following the pattern described previously. Notice the accidentals required to make the pattern work for this particular tonic.

A key signature indicates which notes need to be played sharp or flat. These notes will correspond to the scale associated with that key. For example, the key signature for D major will have the exact same accidentals as the D major scale; two sharps, F# and C#. Instead of writing the accidentals on every note in the music, the key signature serves as a reminder that every F and C, regardless of what octave they’re in, are to be played sharp instead of natural.

The key signature for a minor key (e.g., G minor) uses the accidentals from the natural minor scale. Depending on the musical context, other forms of the minor scale are used. In those cases, the key signature will remain the same and accidentals will be applied as necessary.

As with scales, key signatures follow a pattern. This pattern is the order of sharps and flats. Every key signature follows this pattern regardless of how many sharps or flats are in the key. The order of sharps is F, C, G, D, A, E, B. Sharp key signatures always start on F# and go down to C#, up to G#, down to D#, down again to A#, up to E#, and then down to B#.

The order of flats is the exact opposite of sharps; B, E, A, D, G, C, F. Flat key signatures start on Bb and go up to Eb, down to Ab, and continue in this alternating pattern.

The order and pattern of sharps and flats is the same for all clefs.