Double sharp

What it means

The double sharp raises a natural note by two semitones. F becomes F𝄪 (German fisis), G becomes G𝄪 (German gisis). In sound the result coincides in each case with a note that is simpler to write — F𝄪 sounds like G — but the spelling is not arbitrary: it records which degree is meant and in which direction the note goes on. A note raised to be a leading tone must remain recognizable as a raised degree so that the voice-leading in the notation is correct.

In the notation

The sign differs from two sharps placed side by side: it has the shape of a slanted double cross that recalls a lying x, and stands, like every accidental, to the left of the notehead. Its validity extends to the bar line and concerns only the notated octave register. For the reduction to a single raising, a single sharp suffices today, for complete cancellation the natural sign; older editions sometimes write additional combinations here.

Musical use

The most frequent occasion is the secondary dominant in a sharp key. If, in a piece in F♯ minor, the dominant of the dominant is formed, its leading tone requires a double raising — only in this way does the resolution remain legible as a semitone step upward. The sign also occurs in the harmonic form of remoter minor keys, where the seventh degree is raised, and in sequences whose pattern is to look the same on every degree. In functional theory nothing changes in the naming: such a chord remains the double dominant, regardless of how elaborately its notes are written.

The double raising is to be distinguished from enharmonic exchange, in which a note is deliberately reinterpreted and changes its harmonic role.

Performance practice

First determine the sounding note, then the fingering — when reading, otherwise only a single sharp is easily seen. Remember that a single sharp after a double sharp in the same bar means a lowering by a semitone. With chromatically dense passages it helps to speak the passage once slowly with note names before you play it.