Chapter 14:
Keys and their notes

Play in any (not every) key.

About keys

The key of a composition gives the name of the note serving as the tonal center of the piece. It also identifies the underlying scale to be used. The scale specifies which 7 notes, out of the 12 notes in Western music, are diatonic (“in tune”) in that key.

From this scale, the chords in the key are harmonized. See Chapter 8. Major key harmony and Chapter 9. Minor key harmony for details.

Learn fewer keys better

“Practice in all 12 keys” is a common recommendation in music instruction, and it is probably a useful thing to do eventually. But it violates the principle of triage if there are other more productive ways to spend that time.

It’s usually going to be more productive to spend two hours practicing something in C major than 10 minutes practicing it in each of 12 keys.

Transposing keys is much easier on guitar than on an instrument like the piano. On guitar the fingerings in different keys are mostly the same, anchored around a different part of the fretboard. As a result, on guitar it is more efficient to learn a few keys well than it is to practice in every key.

The time to add another key to our practice is when there’s a real-world need to play in that key, or we have become bored with every key we have already practiced. Otherwise, it’s best to continue working with an already-practiced key.

Order of sharps and flats

Of the 12 notes in Western music, 7 are “natural”, represented by letters A-G from the musical alphabet, and 5 are “accidental”, represented by a letter plus a sharp or flat sign.

When all the 12 chromatic notes are arranged in order of ascending fifths, each key adds one more sharp or flat note to those in the key before it. The order in which sharp and flat notes are added also follows a sequence of fifths.

Order of sharps: F C G D A E B (ascending fifths)
Mnemonic: Father Charles Goes Down And Ends Battle

Order of flats: B E A D G C F (the inverse, descending fifths)
Mnemonic: Battle Ends And Down Goes Charles’ Father

Notes in each key

C (Am) no sharps or flats C D E F G A B
G (Em) 1 sharp G A B C D E F#
D (Bm) 2 sharps D E F# G A B C#
A (F#m) 3 sharps A B C# D E F# G#
E (C#m) 4 sharps E F# G# A B C# D#
B (G#m) 5 sharps B C# D# E F# G# A#
F# (D#m) 6 sharps F# G# A# B C# D# E#
Gb (Ebm) 6 flats Gb Ab Bb Cb Db Eb F
Db (Bbm) 5 flats Db Eb F Gb Ab Bb C
Ab (Fm) 4 flats Ab Bb C Db Eb F G
Eb (Cm) 3 flats Eb F G Ab Bb C D
Bb (Gm) 2 flats Bb C D Eb F G A
F (Dm) 1 flat F G A Bb C D E

Finding the sharp/flat notes in a key

Natural keys

Memorize a couple:

  • C: no sharps or flats
  • F: Bb

Natural keys other than C and F:

  1. Find the key in the order of sharps: F C G D A E B
  2. Find the 2nd note to the left.
  3. All notes in the order of sharps up to the second note to the left are sharp.

Ex. key of E has F# C# G# D#

Flat keys

  1. Find the key in the order of flats: B E A D G C F
  2. Find the note to the right.
  3. All notes in the order of flats up to the note to the right are flat.

Ex. key of Db has Bb Eb Ab Db Gb

Sharp keys

Figure out notes in the natural key, and sharpen every one.

The circle of fifths

Circle of fifths, by 'Just plain Bill' on Wikipedia. See copyright page for details.
Circle of fifths, by 'Just plain Bill' on Wikipedia. See copyright page for details.