Editing Enharmonic equivalence (section)

==Enharmonic key==
Some [[key signature]]s have an enharmonic equivalent that contains the same pitches, albeit spelled differently. In twelve-tone equal temperament, there are three pairs each of major and minor enharmonically equivalent keys: [[B major]]/[[C-flat major|C{{Music|flat}} major]], [[G-sharp minor|G{{Music|sharp}} minor]]/[[A-flat minor|A{{Music|flat}} minor]], [[F-sharp major|F{{Music|sharp}} major]]/[[G-flat major|G{{Music|flat}} major]], [[D-sharp minor|D{{Music|sharp}} minor]]/[[E-flat minor|E{{Music|flat}} minor]], [[C-sharp major|C{{Music|sharp}} major]]/[[D-flat major|D{{Music|flat}} major]] and [[A-sharp minor|A{{Music|sharp}} minor]]/[[B-flat minor|B{{Music|flat}} minor]].

If a key were to use more than 7 sharps or flats it would require at least one double flat or double sharp. These key signatures are extremely rare since they have enharmonically equivalent keys with simpler, conventional key signatures. For example, [[G sharp major]] would require eight sharps (six sharps plus F double-sharp), but would almost always be replaced by the enharmonically equivalent key signature of [[A flat major]], with five flats.