Glebe Terrace

There are a small number of simple methods to work out keys & their key signatures.  Knowing these removes the mystery and increases both understanding & the ability to move beyond a single key.

I´ll state the methods and then go into a bit more detail – still keeping it simple – on some of the terminology and groupings of keys.  This is not intended to be the fastest way of identifying the keys & key signatures, merely a robust and reliable way of being able to write them all out.  With a little practise the entire set can be written out quickly and easily without mnemonic rhymes or rote learning.

All keys take their name from the first note of their scale.  So if the first note of a major key´s scale is F^# the key is F^# Major; if the first note is F the key is F Major.

When working out the keys & their signatures It really helps to have a (piano) keyboard in front of you, or at the very least a picture of one.

3 Octave Kyboard

Major Keys with Sharps

Method

We start with C Major which has no sharps or flats.  The steps to work out the keys & their signatures are:

1. To find the next key, with the right hand play the tonic chord of the current key – this is made up of the 1^st, 3^rd, & 5^th notes of the scale.
2. The next key is the upper note of this chord, ie the 5^th.
3. Keep your hand in the same position on the keyboard.  To get the key signature for the new key, find the note between the upper two of the three fingers that are playing (this is the 4^th of the original key and the 7^th of the new key) sharpen^* it and add this onto the previous key´s signature.
   * Sharpen means to move the note up one semi-tone.
4. Repeat

Examples

C Major this is the starting point, no sharps or flats.  To find the next key & its signature: 1) play the tonic chord C, E, G.  2) This gives the next key as G Major.  3) F is the 7^th, so F^# is added onto the previous key´s signature.  Thus G Major has the key signature: one sharp F; or F^#.

To find the next key & its signature: 1) play the tonic chord of G Major G, A, D.  2) This gives the next key as D Major.  3) C is the 7^th, so C^# is added onto the previous key´s signature.  Thus D Major has the key signature: two sharps F, & C; or F^#, C^#.

Minor Keys with Sharps

There are three sets of minor keys: natural, harmonic, and melodic.  The melodic keys are too complex to provide examples in a simple introduction, but is worth noting that they exist and the method will be stated.

Method – Natural

The easiest way is to work out each key as the relative minor of one of the Major Keys with Sharps.

1. Take each Major Key with Sharps and lower the key by three semi-tones, this gives the 1^st of the minor key.
2. The key signature remains unchanged.

Examples

C Major has no sharps or flats.  1) Three semi-tones down from C is A, the key is A Minor.  2) The key signature is the same as C Major, ie no sharps or flats.

G Major has one sharp F.  1) Three semi-tones down from G is E, the key is E Minor.  2) The key signature is the same as G Major, ie one sharp F.

D Major has two sharps F, & C.  1) Three semi-tones down from D is B, the key is B Minor.  2) The key signature is the same as D Major, ie two sharps F, & C.

Method – Harmonic

An harmonic minor is the same as a natural minor with the addition of a sharpened 7^th so raise the seventh note by one semi-tone.  If the seventh is already a sharp then raise it again anyway.

1. Take each Major Key with Sharps and lower the key by three semi-tones, this gives the 1^st of the minor key.
2. Sharpen the 7^th and add to the Major key´s signature.

Examples

C Major has no sharps or flats.  1) Three semi-tones down from C is A, the key is A Minor.  2) The seventh note of the new key is G, sharpen this to G^#, add this to the key signature of C Major.  Thus the key signature of A Minor is one sharp G.

G Major has one sharp F.  1) Three semi-tones down from G is E, the key is E Minor.  2) The seventh note of the new key is D, sharpen this to D^#, add this to the key signature of G Major.  Thus the key signature of E Minor is two sharps F, & D.

D Major has two sharps F, & C.  1) Three semi-tones down from D is B, the key is B Minor.  2) The seventh note of the new key is A, sharpen this to A^#, add this to the key signature of G Major.  Thus the key signature of E Minor is two sharps F, & D.

C^# Major has seven sharps F, C, G, D, A, E, & B.  1) Three semi-tones down from C^# is A^#, the key is A^# Minor.  2) The seventh note of the new key is G^#, sharpen this to G^## or G^x, whilst this is effectively an A, we refer to it as G^x because this is what we play when we see a note written as G.  Add this to the key signature of C^# Major; thus the key signature of A^# Minor is seven sharps F, C, G^#, D, A, E, & B; or F^#, C^#, G^x, D^#, A^#, E^#, & B^#.

Melodic

A melodic minor is the same as a natural minor with the addition of a sharpened 6^th & 7^th but only when go up the scale, they are unchanged when coming down.

Major Keys with Flats

Method

We start with C Major which has no sharps or flats.  The steps to work out the keys & their signatures is very similar to that for the Major Keys with Sharps:

1. To find the next key, with the left hand play the 4^th chord of the current key (play it with the hand as a mirror of the right playing the tonic chord) – working down the scale this is made up of the 1^st, 6^th, & 4^th notes of the scale.
2. The next key is the lower note of this chord, ie the 4^th.
3. Keep your hand in the same position on the keyboard.  To get the key signature for the new key, find the note between the upper two of the three fingers that are playing (this is the7^th of the original key and the 4^th of the new key) flatten^* it and add this onto the previous key´s signature.
   * Flatten means to move the note down one semi-tone.
4. Repeat

Examples

C Major this is the starting point, no sharps or flats.  To find the next key & its signature: 1) Play the 4^th chord downwards, C, A, F.  2) This gives the next key as F Major.  3) Play the 4^th chord downwards, F, D, B.  4) B is the 4^th, so B^b is added onto the previous key´s signature (which was no sharps or flats).  Thus F Major has the key signature: one flat B; or B^b.

To find the next key & its signature:  1) Play the 4^th chord of F Major downwards, F, D, B^b (this is only a slight variation from step 3 of the previous example).  2) This gives the next key as B^b Major.  3) Play the 4^th chord downwards, B^b, G, E.  4) E is the 4^th, so E^b is added onto the previous key´s signature.  Thus B^b Major has the key signature: two flats B, & E; or B^b, E^b.

Minor Keys with Flats

There are three sets of minor keys: natural, harmonic, and melodic.  As with the sharps, the melodic keys are too complex to provide examples in a simple introduction, but is worth noting that they exist and the method will be stated.

Method – Natural

The easiest way is to work out each key as the relative minor of one of the Major Keys with Flats.

1. Take each Major Key with Flats and lower the key by three semi-tones, this gives the 1^st of the minor key.
2. The key signature remains unchanged.

Examples

C Major has no sharps or flats.  1) Three semi-tones down from C is A, the key is A Minor.  2) The key signature is the same as C Major, ie no sharps or flats.

F Major has one flat B.  1) Three semi-tones down from F is D, the key is D Minor.  2) The key signature is the same as F Major, ie one flat B.

B^b Major has two flats B, & E.  1) Three semi-tones down from B^b is G, the key is G Minor.  2) The key signature is the same as B^b Major, ie two flats B, & EC.

Method – Harmonic

An harmonic minor is the same as a natural minor with the addition of a sharpened 7^th – yes even though we´re dealing with flats we still sharpen the seventh – so raise the seventh note by one semi-tone.  If the seventh is a natural make it a sharp, if it is a flat then make it a natural.

1. Take each Major Key with Flats and lower the key by three semi-tones, this gives the 1^st of the minor key.
2. Sharpen the 7^th and add to the Major key´s signature.

Examples

C Major has no sharps or flats.  1) Three semi-tones down from C is A, the key is A Minor.  2) The seventh note of the new key is G, sharpen this to G^#, add this to the key signature of C Major.  Thus the key signature of A Minor is one sharp G.  Note that this is consistent with the results from the keys with sharps.

F Major has one flat B.  1) Three semi-tones down from F is D, the key is D Minor.  2) The seventh note of the new key is C, sharpen this to C^#, add this to the key signature of F Major.  Thus the key signature of D Minor is one flat B and one sharp C.

B^b Major has two flats B, & E.  1) Three semi-tones down from B^b is G, the key is G Minor.  2) The seventh note of the new key is F, sharpen this to F^#, add this to the key signature of B^b Major.  Thus the key signature of G Minor is two flats B, & E and one sharp F.

E^b Major has three flats B, E, & A.  1) Three semi-tones down from E^b is C, the key is C Minor.  2) The seventh note of the new key is B^b, sharpen this to B, add this to the key signature of E^b Major.  Thus the key signature of C Minor is two flats E, & A.

Melodic

A melodic minor is the same as a natural minor with the addition of a sharpened 6^th & 7^th but only when go up the scale, they are unchanged when coming down.