C♭ major is a musical key that consists of the notes C♭, D♭, E♭, F♭, G♭, A♭, and B♭. It is often considered a theoretical key because it has seven flats, making it less common in practice. The key signature of C♭ major is similar to that of B major, which has five sharps, but it is used in specific contexts, such as in orchestral music. In terms of relative keys, C♭ major is related to A♭ minor, which shares the same key signature. Composers may choose C♭ major for its unique sound and to create specific emotional effects in their music. While it may not be frequently used, it plays a role in the broader landscape of music theory.