D-sharp minor
Since D-sharp minor and its enharmonic equivalent both have key signatures of six accidentals, neither one is clearly used instead of the other. For example, using the melodic minor version of D-sharp minor on the harp is very difficult. The B-pedal can be set to the sharp position, but there is no double-sharp position to set the C-pedal at. In Book I of The Well-Tempered Clavier, Bach chose to write the eighth prelude in E-flat minor but the accompanying fugue in D-sharp minor. (In Book II, Bach wrote both the eighth Prelude and Fugue in D-sharp minor.)