Now we know our diatonic scales and we know our key signatures. We are ready to believe that F# is more common than Gb. The more common a name the more familiar it is to us. The common name is the principal name.
Recall how 9 of our 12 notes have two names.
| C# Db | D# Eb | F# Gb | G# Ab | A# Bb | ||||||||||||
| C B# | D | E Fb | F E# | G | A | B Cb | ||||||||||
Well let us do some detective work. How many key signatures is F# in? 7. How many key signatures is Gb in? 3. F# is the principal name of the F# / Gb enharmonic pair.
| Enharmonic names | The enharmonic name that appears in the greater number of key signatures is the principal name | Principal name | |
| B# C | B# is in 1 key signature | C is in 7 key signatures | C |
| C# Db | C# is in 6 key signatures | Db is in 4 key signatures | C# |
| D | D | ||
| D# Eb | D# is in 4 key signatures | Eb is in 6 key signatures | Eb |
| E Fb | E is in 7 key signatures | Fb is in 1 key signature | E |
| F E# | F is in 7 key signatures | E# is in 2 key signatures | F |
| F# Gb | F# is in 7 key signatures | Gb is in 3 key signatures | F# |
| G | G | ||
| G# Ab | G# is in 5 key signatures | Ab is in 5 key signatures | Ab |
| A | A | ||
| A# Bb | A# is in 3 key signatures | Bb is in 7 key signatures | Bb |
| B Cb | B is in 7 key signatures | Cb is in 2 key signatures | B |
C# | Eb | F# | Ab | Bb | ||||||||||||
C | D | E | F | G | A | B | ||||||||||