But if the home key is near the bottom of the circle ( a key signature with many accidentals ) , enharmonic equivalence may need to be used because simply adding accidentals will result in a key with too many accidentals to be easy to play or write in . But if the home key is near the bottom of the circle ( a key signature of many accidentals ) , and particularly if the related key is on the opposite side , it becomes necessary to consider enharmonic equivalence .