Building a Key Signature

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

Reminders

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

  • Start by writing just the natural notes. You’ll fill in the sharps and flats later.
  • This ensures that you use each letter exactly once. The 8th note doesn’t count as using a note twice because the scale has only seven notes. The first seven notes are all different. The eighth note is just the scale starting over again.

Do This!

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.”

  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.
  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.
  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.
  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.
  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.
  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.

  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.
  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.

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♯.