What is a double sharp?
The double sharp is an accidental that raises the sound of a music note by two whole steps (two semitones ).
In other words, the double sharp raises the sound of the note by one whole step (tone ).
What does the double sharp look like?
Here is how the double sharp is symbolized on a staff (stave ):
There are two ways to write the double sharp:
- with two sharp symbols.
- with a cross-shaped symbol.
Here is a G double sharp, which like any accidental, is placed before the altered note:
As there is only one whole step between G and A, playing a G double sharp is like playing an A on a piano, because this accidental raises the sound by two whole steps:
Why complicate things when they can be simple?
The note G double sharp will never be an A note, a G double sharp will always be a G double sharp, and one of the reasons is very simple, let's take the A sharp Major scale, even if it is rarely used:
In this scale, there are three double accidentals: a C double sharp, a F double sharp and a G double sharp. When the G double sharp note is played on a piano keyboard, it is played with the same key as an A note. Let's imagine that we replace the C♯♯ by a D, the F♯♯ by a G and the G♯♯ by an A, it becomes absurd, because just like in the C major scale, the names of notes follow each other (C D E F G A B), and theoretically, we cannot have fun replacing notes by enharmony when it suits us. The A sharp Major scale is A♯ B♯ C♯♯ D♯ E♯ F♯♯ G♯♯ A♯ and not A♯ B♯ D D♯ E♯ G A A♯, because otherwise we can write the C major scale like this: C C♯♯ E G♭♭ F♯♯ A C♭ B♯? Absurd, right?
Famous works using the double sharp
The composers of the Romantic period often used keys with a lot of accidentals, we will certainly find lots of double accidentals in Frédéric Chopin's piano music, let's look at the Nocturnes for piano.
Chopin, Nocturne opus 9 n°3
Frédéric Chopin's Nocturne opus 9 n°3 begins with a measure (bar ) containing a double sharp, just after the anacrusis. You will notice the use of the rhythm known as the Siciliano rhythm. There are also double sharps in measures 9 and 11:
Chopin, Nocturne opus 15 n°2
Frédéric Chopin's Nocturne opus 15 n°2 includes double sharps (measures 5,10,12):
(Royalty-free sample performed by pianist Samson François in 1964, Creative Commons Zero 1.0 license, source).
You will notice that this work uses a key rarely used used: F sharp Major. You will also notice the use of an anacrusis, trills (measure 7), sixteenth note quintuplets (measure 3), and sixteenth note septuplets (measure 10).
J.S. Bach, fugue no.8 of the Well-Tempered Clavier, book I
The fugue no.8 in D sharp minor from the first book of the Well-Tempered Clavier by Johann Sebastian BACH (Das wohltemperierte Klavier I, BWV 846-869) also includes double sharps:
Royalty-free sound sample recorded by pianist Kimiko Ishizaka in 2015 (CC BY 4.0 license, source).
This key is not very practical nor very used, some editors propose a version of this fugue in the enharmonic key of E flat minor.
You will notice the use of mordents.
The prelude which precedes this fugue is composed in the enharmonic key in D sharp minor, that is to say in E flat minor.
J.S. BACH, Fugue n°18 BWV 863
Fugue n°18 BWV 863 in G sharp minor (book 1 of the Well-Tempered Clavier) by J.S. BACH includes double sharps:
Royalty-free sound sample recorded in 2015 by pianist Kimiko Ishizaka (Attribution 4.0 International license, source).
You will notice the use of a double alteration "natural / sharp": The natural sign cancels the effect of the sharp in the key signature and the sharp raise the note by a half step (semitone ). Double accidentals like "natural / sharp" or "natural / flat" are now obsolete, a single accidental is now sufficient by convention.