This walks through the basic rules of determining the key signature of a specific piece.

1. Key Signatures (Simplified)

2. Scales
● If you read through Understanding Scales
then you know that our Western two scales
Major and Minor are built off the Harmonic
Sequence

3. Letter Names
● Because of the original 7 degrees of the
scale we assign the first notes of that
scale letter names
● A, B, C, D, E, F, G
● The half steps in between are designated
with a # (sharp) for the note above or a
(flat) for the note below♭

4. 12 Keys
● This also means that some keys can have
two names (the key of G# is the same as
A )♭
● To simplify things, we will focus on the 12
possible keys (not their enharmonic
equivalents)
● A B C D E F G A B D E♭ ♭ ♭ ♭F# (or G )♭

5. Memorize these Two Keys
● C Major (no sharps
or flats)
● F Major (one flat B )♭

6. Two Tricks
● All other key signatures can be determined
by two simple rules
● Rule for Sharps: It's the note above the last
sharp of the key signature.
● Rule for Flats: It's the second to last flat
● This is assuming the piece is Major, we'll
worry about Minor later.

7. Using the Rules
● The last sharp in the
key signature is the
second line from the
top – in Treble Clef
that is a D
● Therefore the key
signature is the note
above D – E Major

8. Using the Rules
● The second to last flat
is on the second
space from the bottom
– in the Treble Clef
that is an A
● Therefore the key
signature is A♭

9. All Keys
● No Sharps or Flats –
You memorized this
● C Major
● Relative Minor: A minor

10. All Keys
● One Sharp – F#
● G Major
● Relative Minor: E minor

11. All Keys
● Two Sharps – Last is C#
● D Major
● Relative Minor: B minor

12. All Keys
● Three Sharps – Last is G#
● A Major
● Relative Minor: F# minor

13. All Keys
● Four Sharps – Last is D#
● E Major
● Relative Minor: C# minor

14. All Keys
● Five Sharps – Last is A#
● B Major
● Relative Minor: G# minor

15. All Keys
● 6 Sharps – Last is E#
● F# Major
● 6 Flats – Second to last
● G Major♭
● Relative Minor: D# minor or E minor♭

16. All Keys
● Five Flats – Second to last
● D Major♭
● Relative Minor: B minor♭

17. All Keys
● Four Flats – Second to last
● A Major♭
● Relative Minor: F minor

18. All Keys
● Three Flats – Second to last
● E Major♭
● Relative Minor: C minor

19. All Keys
● One Flats – You memorized
● F Major
● Relative Minor: D minor

20. Bonus Slide
● Here's what happens if we diagram these
keys out – it's called the Circle of Fifths