When an instrument has several staves (e.g. the upper and lower staves in a grand-staff) it is necessary a mechanism to specify in which staff a note, rest, clef, or other must be placed. For this purpose, an element p is used.

It can be abbreviated by omitting the parenthesis and joining the p and the number. Example:

'(p 2)' is equivalent to 'p2'

Staffs are numbered from top to bottom, starting at staff 1. The staff number is inherited by all coming elements until a new p notation is found.

Example: a scale across two staves:

(instrument (staves 2)
    (musicData
        (clef G p1)(clef F p2)(key C)
        ng3w,p2 na nb nc4 nd,p1 ne nf ng
        (barline double)
    )
)

Clef G is placed in first staff (p1) and clef F in second staff (p2). The key is common to all staves of one instrument so no staff is specified. First note (G3) is placed on second staff and consecutive notes inherits this, until note D4 for which location on first staff is specified (p1). Remaining notes inherits this.