C-sharp major

What it means

C-sharp major is the major key built on C-sharp and requires seven sharps (C♯, D♯, E♯, F♯, G♯, A♯, B♯), raising every one of the seven natural notes. It is therefore the major key with the highest number of sharps in the circle of fifths. Its relative minor is A-sharp minor.

Musical use

Because of the cumbersome notation with seven sharps, C-sharp major is in practice often replaced by its enharmonic equivalent, D-flat major, with only five flats and easier reading. On equal-tempered instruments such as the piano the two keys sound identical, though they differ in notation and, on unequally tempered instruments or string instruments, can differ slightly in sound.

Composers usually choose C-sharp major deliberately when a harmonic relationship to an already established sharp key, such as F-sharp major or C-sharp minor, is in the foreground, while D-flat major tends to appear alongside flat keys.

Performance practice

If you meet a piece in C-sharp major, first get your bearings from the seven sharps and practice the scale slowly before playing the piece; if it helps, you can mentally “translate” the piece into D-flat major to grasp the fingerings more easily.