Possible Clues:

• Note after G
• Key of Chopin's "Heroic Polonaise"
• Key of Chopin's first Opus 25 étude
• Black key
• Key of two Schubert impromptus
• Schubert's 'Mass in ___ major'
• Take note of this apartment
• Chopin's 'Polonaise in ___ Major, Op. 53'
• Tough key for pianists
• 'Perhaps a part meant to sound close to 6 down (1,4)'