G-flat major is a major scale based on G-flat, consisting of the pitches , , , , , , and F. Its key signature has six flats (see below: Scales and keys).
Its relative minor is E-flat minor, and its parallel minor is G-flat minor, usually replaced by F-sharp minor, since G-flat minor, which would have five flats and two double-flats, is not normally used.
Its enharmonic equivalent is F-sharp major, whose key signature also has six accidentals. In writing music in E major for B-flat instruments, it is preferable to use a G-flat rather an F-sharp key signature.
Rarely chosen as the main key for orchestral works, G-flat major is more often used as a main key for piano works, such as the impromptus of Chopin and Schubert.
Austrian composer Gustav Mahler was fond of using G-flat major in key passages of his symphonies; examples include: The choral entry during the finale of his Second Symphony, during the first movement of his Third Symphony, the modulatory section of the Adagietto from his Fifth Symphony, and during the Rondo-Finale of his Seventh Symphony. Mahler's Tenth Symphony was composed in the enharmonic key of F sharp major.
