Chapter 3 - Keys

Objectives: In this chapter, you'll learn what keys are and write out the notes in all 12 keys.

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What's a Key

A key (in music) is a group of notes that a song or musical idea is based on. This is usually referred to as the tonal center. Keys are almost identical to scales. However, while a scale is a group of notes played in a specific order, a key is the use of a scale where the notes can be played in any order. For example, a song in the key of C uses the notes from C major scale and has a tonal center of C major. A song in the key of B♭ uses the notes from the B♭ major scale and has a tonal center of B♭.

Here's a C major scale:

And here's a song in the key of C (using notes from the C Major scale):

You would say a song is in a certain key, but you wouldn't say a song is in a certain scale. To use both in a sentence, you might say, "This song is in the key of C, so use a C major scale to improvise."

Key Signatures

A key signature is like a fingerprint for a key. It identifies a key as being different from all other keys. Key signatures are expressed as a collection of sharps and flats. For example, the key signature for the key of C is "no sharps or flats" because the notes in the key (and the C major scale) are just the natural notes C, D, E, F, G, A, and B. The key signature for the key of D is "two sharps, F♯ and C♯." Why is that the key signature? You'll learn that later in this chapter. For now, just understand that a key signature is simply a list of sharps and flats in a certain key. You actually played through all the keys in the last chapter when you played all 12 scales.

Mixing Sharps and Flats

Major scales never have both sharps and flats. The key signature for any major scale will have just flats, just sharps, or none (as with the key of C). Also, every major scale has a different number of sharps and flats. For example, only one major scale has one sharp, only one major scale has two sharps, only one major scale has one flat, etc.

Writing Key Signatures

To properly write out a key signature, you need to know a little about reading music. We'll learn how to do that later. For now, we'll simply write out key signatures as a list of sharps or flats.

Once you know how to read music, you'll be able to read this key signature and tell it's the key of D.
key signature of D major

For now, we can simply write the key signature for D major like this:
F♯ C♯
or we can write out all of the notes in the key as a chart, like this:
D E F♯ G A B C♯ D

Don't worry if you don't know why the key of D major has an F♯ and a C♯. You haven't learned that yet. That's what the rest of this chapter is about! In the next lessons, you'll learn how to figure out the key signature for every major key and write it out as a chart.

Key Signature Order

When writing the sharps and flats of a key signature, they should be written in the correct order. For example, in the key of D major:
F♯ C♯ is correct while
C♯ F♯ is incorrect.

This has to do with the way in which the sharps and flats are arranged in written music like this:
key signature of D major

I'll show you the orders now, but don't worry about memorizing them. I'll put them here just to satisfy your curiosity. Why the order matters is something we'll get to much later in a different chapter when you start reading music.

Order of Sharps

Order of Flats

Key of C

Since the key of C major uses the notes in the C major scale, you need to construct the C major scale. If you do that and identify the sharps and flats (if there are any), you'll have figured out the key signature for the key of C major. You already figured out all of the notes in the C major scale in a previous chapter. Let's do that again but this time focus on building the key signature.

You'll need your guitar with you as you do this, but first get a sheet of paper and a pencil. Write, "C Major" at the top. Under that, write out a starting template with all the letter names like this:
C D E F G A B C
Sheet of paper with student work

A few things to remember when writing out a key chart like this one:

Now grab your guitar and follow these steps:

  1. Since we want a C scale, we need to find a C note to start. Let's choose the 2nd string at the 1st fret. We'll also label the degree below the note so we keep track of where we are in the scale. Remember that the formula for a major scale says there's a half-step between degrees 3-4 and 7-8. Play the starting C note and say out loud, "First degree, C."
    Guitar fretboard with C labeled
  2. Now, say out loud, "From one to two is a whole step. A whole step higher than C is D." Move up a whole step (two frets) and play the D. Since we didn't use a sharp or flat, we don't need to update our piece of paper.
    Guitar fretboard with C and D labeled
  3. Now, say out loud, "From two to three is a whole step. A whole step higher than D is E." Move up a whole step (two frets) and play the E. Since we didn't use a sharp or flat, we don't need to update our piece of paper.
    Guitar fretboard with C, D and E labeled
  4. Now, say out loud, "From three to four is a half-step. A half-step higher than E is F." Move up a half-step (one fret) and play the F. Since we didn't use a sharp or flat, we don't need to update our piece of paper.
    Guitar fretboard with C, D, E, and F labeled
  5. Now, say out loud, "From four to five is a whole step. A whole step higher than F is G." Move up a whole step (two frets) and play the G. Since we didn't use a sharp or flat, we don't need to update our piece of paper.
    Guitar fretboard with C, D, E, F, and G labeled
  6. Now, say out loud, "From five to six is a whole step. A whole step higher than G is A." Move up a whole step (two frets) and play the A. Since we didn't use a sharp or flat, we don't need to update our piece of paper.
    Guitar fretboard with C, D, E, F, G, and A labeled
  7. Now, say out loud, "From six to seven is a whole step. A whole step higher than A is B." Move up a whole step (two frets) and play the B. Since we didn't use a sharp or flat, we don't need to update our piece of paper.
    Guitar fretboard with C, D, E, F, G, A, and B labeled
  8. Finally, say out loud, "From seven to eight is a half-step. A half-step higher than B is C." Move up a half-step (one fret) and play the C.
    Guitar fretboard with C, D, E, F, G, A, B, and C labeled
  9. There you have it - all the notes in a C major scale, which are all the notes in the key of C major. There are no sharps or flats so we didn't need to update our piece of paper. So the key signature for C major is: no sharps or flats.
    Sheet of paper with student work showing all notes in the key of C

You've waited for it long enough. In the next lesson you'll learn why the key of D Major has a key signature of F♯ and C♯.

Key of D

Since the key of D major uses the notes in the D major scale, you need to construct the D major scale. If you do that and identify the sharps and flats, you'll have figured out the key signature for the key of D major. You already figured out all of the notes in the D major scale in a previous chapter. Let's do that again but this time focus on building the key signature. Have your guitar with you as you do this. The goal is to identify any sharps or flats.

Write "D Major" under your work from the last lesson. Under that, write out a starting template with all the letter names like this:
D E F G A B C D
Sheet of paper with student work starting to write notes in the key of D

  1. Since we want a D scale, we need to find a D note to start. Let's choose the 4th string open since it's the D string. We'll also label the degree below the note so we keep track of where we are in the scale. Play the starting D note and say out loud, "First degree, D."
    Guitar fretboard with D labeled
  2. Now, say out loud, "From one to two is a whole step. A whole step higher than D is E." Move up a whole step (two frets) and play the E. Since we didn't use a sharp or flat, we don't need to update our piece of paper.
    Guitar fretboard with D and E labeled
  3. Now, say out loud, "From two to three is a whole step. A whole step higher than E is F♯." Move up a whole step (two frets) and play the F♯. Remember that E to F is only a half-step, but we need a whole step between scale degrees 2-3. Going from E to F gives us only a half-step, so we need to bump that F up to F♯ to get our whole step. Now - write the ♯ symbol on your paper after the F to show the F in the key of D is F♯.
    Guitar fretboard with D, E, and F# labeled
    Sheet of paper with student work showing some notes in the key of D
  4. Now, say out loud, "From three to four is a half-step. A half-step higher than F♯ is G." Move up a half-step (one fret) and play the G.
    Guitar fretboard with D, E, F#, and G labeled
  5. Now, say out loud, "From four to five is a whole step. A whole step higher than G is A." Move up a whole step (two frets) and play the A.
    Guitar fretboard with D, E, F#, G, and A labeled
  6. Now, say out loud, "From five to six is a whole step. A whole step higher than A is B." Move up a whole step (two frets) and play the B.
    Guitar fretboard with D, E, F#, G, A, and B labeled
  7. Now, say out loud, "From six to seven is a whole step. A whole step higher than B is C♯." Move up a whole step (two frets) and play the C♯. Just like back at degrees 2-3 and the E and F notes, we need a whole step here at degrees 6-7. But B to C is only a half-step. So we need to bump that C up to C♯ to get our whole step. Now - write the ♯ symbol on your paper after the C to show the C in the key of D is C♯.
    Guitar fretboard with D, E, F#, G, A, B, and C# labeled
    Sheet of paper with student work showing with all notes in the key of D
  8. Finally, say out loud, "From seven to eight is a half-step. A half-step higher than C♯ is D." Move up a half-step (one fret) and play the D.
    Guitar fretboard with all notes in the key of D labeled
  9. There you have it - all the notes in a D major scale, which are all the notes in the key of D major. There are two sharps: F♯ and C♯. So the key signature for D major is: F♯ and C♯.
    Sheet of paper with student work showing with all notes in the key of D

Let's try one in the next lesson that's a bit more challenging - the key of A.

Key of A

Since the key of A major uses the notes in the A major scale, you need to construct the A major scale. Have your guitar with you as you do this. The goal is to identify any sharps or flats.

Write "A Major" under your work from the last lesson. Under that, write out a starting template with all the letter names like this:
A B C D E F G A
Sheet of paper with student work starting to write all notes in the key of A

  1. Since we want an A scale, we need to find an A note to start. Let's choose the 5th string open since it's the A string. We'll also label the degree below the note so we keep track of where we are in the scale. Play the starting A note and say out loud, "First degree, A."
    Guitar fretboard with A labeled
  2. Now, say out loud, "From one to two is a whole step. A whole step higher than A is B." Move up a whole step (two frets) and play the B.
    Guitar fretboard with A and B labeled
  3. Now, say out loud, "From two to three is a whole step. A whole step higher than B is C♯." Move up a whole step (two frets) and play the C♯. Remember that B to C is only a half-step, but we need a whole step between scale degrees 2-3. Going from B to C gives us only a half-step, so we need to bump that C up to C♯ to get our whole step. Now - write the ♯ symbol on your paper after the C to show the C in the key of A is C♯.
    Guitar fretboard with A, B, and C# labeled
    Sheet of paper with student work showing some notes from the key of A
  4. Now, say out loud, "From three to four is a half-step. A half-step higher than C♯ is D." Move up a half-step (one fret) and play the D.
    Guitar fretboard with A, B, C#, and D labeled
  5. Now, say out loud, "From four to five is a whole step. A whole step higher than D is E." Move up a whole step (two frets) and play the E.
    Guitar fretboard with A, B, C#, D, and E labeled
  6. Now, say out loud, "From five to six is a whole step. A whole step higher than E is F♯." Move up a whole step (two frets) and play the F♯. Now - write the ♯ symbol on your paper after the F to show the F in the key of A is F♯.
    Guitar fretboard with A, B, C, D, E, and F# labeled
    Sheet of paper with student work showing some notes in the key of A
  7. Now, say out loud, "From six to seven is a whole step. A whole step higher than F♯ is G♯." Move up a whole step (two frets) and play the G♯. Now - write the ♯ symbol on your paper after the G to show the G in the key of A is G♯.
    Guitar fretboard with A, B, C#, D, E, F#, and G# labeled
    Sheet of paper with student work showing all notes in the key of A
  8. Finally, say out loud, "From seven to eight is a half-step. A half-step higher than G♯ is A." Move up a half-step (one fret) and play the A.
    Guitar fretboard with A, B, C#, D, E, F#, G#, and A labeled
  9. There you have it - all the notes in an A major scale, which are all the notes in the key of A major. There are three sharps: F♯, C♯ and G♯. So the key signature for A major is: F♯, C♯ G♯.
    Sheet of paper with student work showing all notes in the key of A

Let's do one more in the next lesson with flats.

Key of E♭

Since the key of E♭ major uses the notes in the E♭ major scale, you need to construct the E♭ major scale. Have your guitar with you as you do this. The goal is to identify any sharps or flats.

Write "E♭ Major" under your work from the last lesson. Under that, write out a starting template with all the letter names like this:
E♭ F G A B C D E♭
Sheet of paper with student work showing some notes in the key of E-flat

  1. Since we want an E♭ scale, we need to find an E♭ note to start. Let's choose the 1st fret of the 4th string. We'll also label the degree below the note so we keep track of where we are in the scale. Play the starting E♭ note and say out loud, "First degree, E♭."
    Guitar fretboard with E-flat labeled
  2. Now, say out loud, "From one to two is a whole step. A whole step higher than E♭ is F." Move up a whole step (two frets) and play the F.
    Guitar fretboard with E-flat and F labeled
  3. Now, say out loud, "From two to three is a whole step. A whole step higher than F is G." Move up a whole step (two frets) and play the G.
    Guitar fretboard with E-flat, F, and G labeled
  4. Now, say out loud, "From three to four is a half-step. A half-step higher than G is A♭." Move up a half-step (one fret) and play the A♭. Write the ♭ on your paper after the A.
    Guitar fretboard with E-flat, F, G, and A-flat labeled Sheet of paper with student work showing some notes in the key of E-flat
  5. Now, say out loud, "From four to five is a whole step. A whole step higher than A♭ is B♭." Move up a whole step (two frets) and play the B♭. Write the ♭ symbol on your paper after B.
    Guitar fretboard with E-flat, F, G, A-flat, and B-flat labeled Sheet of paper with student work showing all notes in the key of E-flat
  6. Now, say out loud, "From five to six is a whole step. A whole step higher than B♭ is C." Move up a whole step (two frets) and play the C.
    Guitar fretboard with E-flat, F, G, A-flat, B-flat, and C labeled
  7. Now, say out loud, "From six to seven is a whole step. A whole step higher than C is D." Move up a whole step (two frets) and play the D.
    Guitar fretboard with E-flat, F, G, A-flat, B-flat, C, and D labeled
  8. Finally, say out loud, "From seven to eight is a half-step. A half-step higher than D is E♭." Move up a half-step (one fret) and play the E♭.
    Guitar fretboard with E-flat, F, G, A-flat, B-flat, C, D, and E-flat labeled
  9. There you have it - all the notes in an E♭ major scale, which are all the notes in the key of E♭ major. There are three flats: B♭, E♭, and A♭. So the key signature for B♭ major is: B♭, E♭, and A♭.
    Sheet of paper with student work showing all notes in the key of E-flat

Challenge

You've already written out all the notes in four keys in this lesson (C, D, A, and E♭). In this challenge, you'll write out the notes in all 12 keys.

You learned in a previous chapter that when a key starts with an enharmonic note name (like D♯/E♭) you should almost always use the ♭ name. The exceptions were F♯/G♭ and C♯/D♭. In those cases, you could use either. But because this is a challenge - challenge yourself! Write out the notes for both versions of all five enharmonic keys. The challenge is figuring out the double sharps and double flats.

Summary

After completing this lesson, you should be able to answer these questions/do these things:

Answer These

Do This