In Western music, there are a total of twelve notes per octave, named A, A#, B, C, C#, D, D#, E, F, F#, G and G# . The sharp notes, or ‘accidentals’, fall on the black keys, while the regular or ‘natural’ notes fall on the white keys. As well as sharps, the black keys can also be flats – ie, Bb, Db, Eb, Gb, and Ab.