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(x) double-sharp

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Double-sharps on the staff.

A Cx and Gx on the staff means you'll play a D and A natural, respectively.

Image © Brandy Kraemer
Definition: A double-sharp is the equivalent of two sharps, and raises a note’s pitch by two semitones. The double-sharp symbol is similar to a bold x, and is placed before a note like other accidentals.

While single sharps usually point to black piano keys, double-sharps often point to piano naturals; G# is a black key, but Gx is otherwise known as A natural (see enharmonic notes).


  • Exceptions to this are B# and E#, which point to the C and F natural keys, respectively; and Bx and Ex, which are the C# and F# keys.

The Purpose of the Double-Sharp

Double-accidentals are not seen in any working key signature. In fact, if there were a key signature after C# major (which has the maximum seven sharps), it would contain one F double-sharp (learn more about theoretical key signatures).

In everyday notation, however, double-sharps are necessary in certain scenarios. Suppose you were composing in the key of C# major (which puts a sharp on every note) and wanted to write an A natural in a measure that already contains some A#’s. Instead of alternating between writing A natural and A sharp, you could instead indicate the tone of A natural with a G double-sharp.

The same rules also apply to chords. In an A# major 7th chord – whose notes are A#  Cx  E#  Gx – the tone of A natural is disguised as Gx.


See (♭♭) double-flat.

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