A-sharp minor has the enharmonic equivalent of B-flat minor . This is often used in most musical compositions instead of A-sharp minor , because A-sharp minor is not a useful key for compositions and is one of the least used minor keys in music . The enharmonic equivalent B-flat minor is often used in most musical compositions instead of A-sharp minor , thus indicating that A-sharp minor is not a practical key for compositions and is one of the least used minor keys in music .