To establish the pitch of any note on the staff we place a graphical symbol called a clef (from the Latin clavis meaning key) at the far left-hand side of the staff. The clef establishes the pitch of the note on one particular line of the staff and thereby fixes the pitch of all the other notes lying on, or related to, the same staff.

It can be helpful to imagine each clef as a part of a 'grander' stave of eleven horizontal lines and ten spaces. The illustration below shows the 'grand stave' (including the treble and bass clef's) with the position of the 'C' or alto clef (which is not covered at this level)


Middle C (the one in the middle of a piano keyboard) is written on the first leger line below the treble stave (treble clef) or one leger line above the bass stave (bass clef) and shown as a red line