C♯ / D♭

C♯ / D♭ is pitch class 1 — one semitone above C and one below D. The two spellings are the same sounding class in equal temperament: C♯ rises from C; D♭ falls from D. Which name you use follows the key signature or the chord spelling, not a change of pitch class.

On the chromatic scale it is the first raised (or first lowered) step away from C. It sits between two naturals and carries no separate “character” of its own on this page — only its place in the twelve.

In major-triad grammar this class is the root of C♯ major (C♯–F–G♯, with F standing for E♯), the major third of A major (A–C♯–E), and the perfect fifth of F♯ major (F♯–A♯–C♯). Alone it stays a pitch class. A vessel offering waits on a full major triad.

Also known as C sharp · C♯ · D flat · D♭ · Db · C#