The staff and the clefs

Musical notation exists so that music can be put down on paper and read back, by someone else or by you yourself, whenever needed. For that to work, a score has to tell you three things: which note you play, how long it lasts, and where you are in the piece. Duration and position are handled by the note values and the meters. The note's identity, that "which note", is set by the staff and the clef together.

01The staff

The staff consists of five horizontal lines and the four spaces between them. That is where the notes are placed: some sit on a line, others inside a space.

On its own, though, the staff does not give you the whole story. If you see a note on the middle line, for example, you cannot tell which note it is. Is it C? B? G?

02What the clef is

The clef solves exactly this problem. It sits at the start of the staff, points at one specific line, and says "on this line lives this note". Every other note follows automatically, walking up or down music's alphabet (C, D, E, F, G, A, B; in solfège, Do, Re, Mi, Fa, Sol, La, Si).

Each clef takes its name from the note it "locks".

03Ledger lines and middle C

Often a note is too high or too low to fit inside the five lines. In those cases we use ledger lines: short horizontal strokes that extend the staff upwards or downwards.

One note deserves a special mention: middle C (C4 in international naming). It sits exactly on the border between the two most common clefs: one ledger line below the treble clef, one ledger line above the bass clef. It is the very same note, written in two different ways.

04The four clefs

Modern notation uses four clefs:

Treble clef (the G clef). Its curl wraps around the second line and "locks" the note G there. It is used for instruments in the middle and high registers, such as the bouzouki, the violin, the piano (right hand) and so on.

Bass clef (the F clef). Its two dots enclose the fourth line, "locking" the note F there. It is used for low-register instruments such as the double bass, the piano (left hand) and so on.

Alto clef (a C clef). The centre of the symbol points at the third line of the staff, "locking" middle C there. It is the clef of the viola.

Tenor clef (the same C clef, moved one line higher). Its centre points at the fourth line, "locking" middle C there. It is used by the cello when it plays high, and by instruments such as the bassoon and the trombone.

05Why four clefs

So why four clefs and not one? The answer is practical. Every instrument plays in a particular range of notes: some high, some low. The clef is chosen so that the instrument's notes fit as much as possible inside the five lines, without a pile of ledger lines.

See how the same bass phrase is written in each of the four clefs:

That is why a bass is always written in the bass clef. By the same logic every instrument picks its clef: the one where its notes fit naturally inside the staff.