C-flat major

C-flat major is a major scale based on C♭, consisting of the pitches C♭, D♭, E♭, F♭, G♭, A♭, and B♭. Its key signature has seven flats. Its relative minor is A-flat minor (or enharmonically G-sharp minor). Its parallel minor, C-flat minor, is usually rewritten as B minor, since C-flat minor's three double-flats make it impractical to use. The direct enharmonic equivalent of C-flat major is B major, a key signature with five sharps.

The C-flat major scale is:

Changes needed for the melodic and harmonic versions of the scale are written in with accidentals as necessary. The C-flat harmonic major and melodic major scales are:

C-flat major is the only major or minor key, other than theoretical keys, which has "flat" or "sharp" in its name, but whose tonic note is the enharmonic equivalent of a natural note, B (a white key on a keyboard instrument).

Scale degree chords

The scale degree chords of C-flat major are:

Tonic – C-flat major

Supertonic – D-flat minor

Mediant – E-flat minor

Subdominant – F-flat major

Dominant – G-flat major

Submediant – A-flat minor

Leading-tone – B-flat diminished

Use in harp music

C-flat major is the home key of the harp, with all its pedals in the top position, and it is considered the most resonant key for the instrument. Thus, in Richard Strauss's Ein Heldenleben, the first cue for the harps is written in C-flat major even though the rest of the orchestra, having previously played in E-flat major, retains a 3-flat key signature and is now playing in B major, marked with the necessary sharps and naturals as accidentals.

This use of C-flat major in harp parts when the rest of the orchestra is playing in B major is not exceptional: it is standard practice in orchestral music written in B major for harp parts to be notated in C-flat major.