Ledger line
An additional line above/below the staff.
What it means
Ledger lines (German Hilfslinien, “auxiliary lines”) are short pieces of line above or below the five-line staff that make it possible to notate notes outside the staff. The staff itself holds only a limited tonal space; everything above and below it needs a continuation of the grid of lines, which, however, reaches only as far as the respective note requires. The distance between the ledger lines corresponds to that of the staff lines, so that counting continues without a gap.
In the notation
The lines are drawn in each case long enough that they project just beyond the notehead on both sides; with several ledger lines one above the other the distance stays the same. If a note lies in the space above the last line drawn, it needs no further one. Middle C is the best-known case: it lies on the first ledger line below the treble clef and on the first above the bass clef — the same note, two spellings, and it is precisely at this point that the two staves of the piano texture touch.
To avoid many ledger lines, two means are available: the change of clef and the octave marking, which lets the score be read displaced by an octave. The C clef in particular owes its mobility to this purpose.
Musical use
From about three to four ledger lines onward, reading becomes noticeably slower, because the eye no longer has a fixed order of reference and has to count. Music engraving therefore tries to keep their number small. In practice many ledger lines are nevertheless regularly met, for instance in piano literature with widely separated hands and in high string registers.
Performance practice
Do not count line by line but remember anchor points in the ledger-line area — for instance c‴ above the treble clef — and read the neighbouring notes as a distance from it. Practise the most frequent high and low places of your instrument deliberately so that they become pictures instead of arithmetic problems. Where an edition shows many ledger lines, check whether another edition writes the same passage with octave signs; this eases study considerably.