Handout 10: Keys & Signatures

What You’ll Learn:

What a musical key is (the “home base” of a piece of music)

What key signatures are and how to read them

The order of sharps and flats

How to identify a key from its key signature

Relative major/minor pairs

Enharmonic equivalents (when two names mean the same key)

The complete Circle of Fifths

What Is a Key?

A key is the “home base” of a piece of music. It tells you which scale the music is based on, which note feels like “home,” and which sharps or flats are used throughout the piece.

Think of a key like a neighborhood. If a song is “in the key of C major,” that means:

The note C feels like home (the music keeps returning to it)
The chords and melody are mostly built from the C major scale (C-D-E-F-G-A-B)
There are no sharps or flats (all white keys)

If a song is “in the key of G major,” that means:

G feels like home
The music is built from the G major scale (G-A-B-C-D-E-F#)
There is one sharp: F#

A key determines the entire “flavor” of a piece — which notes and chords will be used most.

Key Signatures: Standing Instructions

Rather than writing a sharp or flat symbol in front of every affected note in a piece, the composer puts the sharps or flats at the very beginning of every staff line. This is the key signature — it acts as a “standing instruction” that applies to the entire piece.

For example, instead of writing a # in front of every F in a G major piece, the composer places one sharp (on the F line) at the beginning. From that point forward, every F is played as F# unless otherwise marked.

   Key of C major:     no sharps, no flats (empty key signature)
   Key of G major:     one sharp (#) on the F line → all Fs are F#
   Key of F major:     one flat (b) on the B line → all Bs are Bb

The Order of Sharps: Father Charles Goes Down And Ends Battle

Sharps are always added in the same specific order. You never get a random sharp — they follow this exact sequence:

   F# → C# → G# → D# → A# → E# → B#

Memory trick: F-C-G-D-A-E-B = “Father Charles Goes Down And Ends Battle”

So:

1 sharp = F#
2 sharps = F#, C#
3 sharps = F#, C#, G#
4 sharps = F#, C#, G#, D#
…and so on

Finding the Major Key from Sharps

Shortcut: The major key is a half step above the last sharp in the key signature.

Examples:

Last sharp is F# → half step above F# = G → Key of G major
Last sharp is C# → half step above C# = D → Key of D major
Last sharp is G# → half step above G# = A → Key of A major

This trick works every time.

The Order of Flats: Battle Ends And Down Goes Charles’ Father

Flats are also added in a specific order — and it is the reverse of the sharps order:

   Bb → Eb → Ab → Db → Gb → Cb → Fb

Memory trick: B-E-A-D-G-C-F = “Battle Ends And Down Goes Charles’ Father”

(Notice it is the sharps order spelled backward!)

So:

1 flat = Bb
2 flats = Bb, Eb
3 flats = Bb, Eb, Ab
4 flats = Bb, Eb, Ab, Db
…and so on

Finding the Major Key from Flats

Shortcut: The major key is the second-to-last flat in the key signature.

Examples:

2 flats (Bb, Eb) → second-to-last flat is Bb → Key of Bb major
3 flats (Bb, Eb, Ab) → second-to-last flat is Eb → Key of Eb major
4 flats (Bb, Eb, Ab, Db) → second-to-last flat is Ab → Key of Ab major

Exception: This trick does not work for 1 flat (there is no “second-to-last”). Just memorize: 1 flat = F major.

All Major Key Signatures

Key	Sharps/Flats	Which Ones
C major	0	—
G major	1#	F#
D major	2#	F#, C#
A major	3#	F#, C#, G#
E major	4#	F#, C#, G#, D#
B major	5#	F#, C#, G#, D#, A#
F# major	6#	F#, C#, G#, D#, A#, E#
F major	1b	Bb
Bb major	2b	Bb, Eb
Eb major	3b	Bb, Eb, Ab
Ab major	4b	Bb, Eb, Ab, Db
Db major	5b	Bb, Eb, Ab, Db, Gb
Gb major	6b	Bb, Eb, Ab, Db, Gb, Cb

For this course, focus on the first few: C (0), G (1#), D (2#), F (1b), Bb (2b).

Relative Major and Minor Pairs

As you learned in Handout 6, every major key has a relative minor that shares the same key signature. The minor key starts on the 6th note of the major scale (or equivalently, a minor 3rd below the major key’s root).

Major Key	Key Signature	Relative Minor
C major	0	A minor
G major	1#	E minor
D major	2#	B minor
A major	3#	F# minor
E major	4#	C# minor
B major	5#	G# minor
F major	1b	D minor
Bb major	2b	G minor
Eb major	3b	C minor
Ab major	4b	F minor
Db major	5b	Bb minor
Gb major	6b	Eb minor

How to tell if a piece is major or minor when they share the same key signature? Listen for the “home” note. If the music feels like it rests on C, it is C major. If it rests on A (with the same no-sharps-no-flats key signature), it is A minor. Also look at the first and last chords — they usually tell you the key.

Transposition: Playing in a Different Key

Transposition means moving a piece of music to a different key — playing the same melody and chords, but higher or lower. The relationships between notes stay the same; only the starting pitch changes.

Why transpose?

A song might be too high or too low for a singer’s voice
Some keys are easier to play on the keyboard
You want a different mood (higher keys can feel brighter; lower keys more somber)

How to transpose: Convert the chords to Roman numerals, then rebuild in the new key.

Example: A song in C uses the chords C - Am - F - G (I - vi - IV - V). To play it in G: G - Em - C - D (I - vi - IV - V in G).

The Roman numerals stay the same; the actual chords change. This is why learning to think in numerals is so powerful.

Enharmonic Equivalents

Sometimes two different names refer to the same key or note. For example:

F# and Gb are the same key on your keyboard (the black key between F and G)
F# major (6 sharps) and Gb major (6 flats) use the same keys but are written differently

These “same sound, different name” pairs are called enharmonic equivalents. Think of them like the same city with two different names in two different languages.

Common enharmonic pairs:

C# = Db
D# = Eb
F# = Gb
G# = Ab
A# = Bb

In practice, musicians choose whichever spelling is simpler. Gb major (6 flats) is preferred over F# major (6 sharps) because… well, 6 of anything is a lot. As a beginner, you will mostly encounter keys with 0-2 sharps or flats, so enharmonics will not be a daily concern yet.

The Complete Circle of Fifths

The Circle of Fifths is the single most important diagram in music theory. It arranges all 12 major keys in a circle, where each key is a perfect 5th apart from its neighbor.

                        C (0)
                  F (1b)     G (1#)
             Bb (2b)             D (2#)
          Eb (3b)                   A (3#)
             Ab (4b)             E (4#)
                  Db (5b)     B (5#)
                     Gb/F# (6b/6#)

How to read it:

Start at the top: C major (no sharps or flats)
Go clockwise: each step adds one sharp (G=1#, D=2#, A=3#, E=4#, B=5#, F#=6#)
Go counterclockwise: each step adds one flat (F=1b, Bb=2b, Eb=3b, Ab=4b, Db=5b, Gb=6b)
Neighbors on the circle are closely related keys — they sound good together

Practical use: The Circle of Fifths tells you:

How many sharps or flats any key has
Which keys are closely related (neighbors on the circle)
The order of sharps and flats (just read around the circle)

For now, focus on the top portion: C, G, D, F, Bb. These are the keys you will use most in this course.

Exercises

Exercise 1: Identify Key Signatures

For each set of sharps/flats, name the major key:

No sharps, no flats → (play C major scale to confirm)
1 sharp (F#) → (play G major scale to confirm)
1 flat (Bb) → (play F major scale to confirm)
2 sharps (F#, C#) → (play D major scale to confirm)

Exercise 2: Find the Relative Minor

For each key above, name and play its relative minor scale:

C major → A minor (play A-B-C-D-E-F-G-A)
G major → E minor (play E-F#-G-A-B-C-D-E)
F major → D minor (play D-E-F-G-A-Bb-C-D)

Exercise 3: Transpose a Progression

Play I-V-vi-IV in C major (C-G-Am-F). Now transpose to G major (G-D-Em-C). Now try F major (F-C-Dm-Bb). Notice the relationships sound the same even though the pitches change.

Exercise 4: Sharp and Flat Order Drill

Say the order of sharps aloud: F-C-G-D-A-E-B (“Father Charles Goes Down And Ends Battle”). Then say the order of flats: B-E-A-D-G-C-F (“Battle Ends And Down Goes Charles’ Father”). Repeat until you can say both without looking.

Starting from C on your CT-X9000IN, play up a 5th to G. From G, up a 5th to D. From D, up a 5th to A. You are walking clockwise around the Circle of Fifths. Now reverse: from C, go down a 5th to F, then down a 5th to Bb. You are walking counterclockwise.

Quick Quiz

What is a key in music? → Answer: The “home base” of a piece of music — it determines which scale the music is built from, which note feels like home, and which sharps or flats are used throughout.
What is the order of sharps? → Answer: F, C, G, D, A, E, B (“Father Charles Goes Down And Ends Battle”)
How do you find the major key from a sharp key signature? → Answer: Go a half step above the last sharp. For example, if the last sharp is C#, a half step above is D, so the key is D major.
What is the relative minor of G major? → Answer: E minor (they share the same key signature: 1 sharp, F#)
What is an enharmonic equivalent? → Answer: Two different names for the same note or key. For example, F# and Gb are the same key on the keyboard — same sound, different spelling.

Key Takeaway

A key is the home base of a piece, and its key signature tells you which sharps or flats apply throughout. Sharps follow the order F-C-G-D-A-E-B; flats reverse it. The Circle of Fifths arranges all 12 keys by their relationship to each other, and is the single most useful reference tool in music theory. Every major key has a relative minor that shares its key signature, and transposition lets you move any song to any key while keeping the musical relationships intact.