Gurus Of Music

Key Signatures And The Circle Of Fifths A 'key signature' shows up at the very beginning of a piece of music, directly after the clef;

The key signature tells you two things; the name of the key and what flats or sharps, if any, are to be applied in the music.  Flats or sharps that appear in a key signature apply to the entire piece, which is different than when they are used as accidentals.
 You can learn more about sharps, flats and accidentals by watching this short video; Accidentals, Whole Steps and Half Steps . There is a scale that goes with each key that starts on the same note as the name of that key. For example; for they key of G Major, the scale would start on G. Any sharps or flats that are in the key signature would apply to that scale. For example; the key of G Major has one sharp which is F, so the scale of G would have an F sharp in it.
 There is a system to the key signatures and understanding it makes using key signatures much clearer and eas...