The Complete Idiot''s Guide to Music Theory

Par t 1:Tones

Minor Keys

The key signatures used to indicate major keys also can represent natural minor

keys. As you remember from Chapter 3, a natural minor scale is based on the

same notes as a major scale, but starts on the sixth note of the scale. This same

method applies to keys, so that (for example) the key of A minor uses the same

notes—and the same key signature—as C major.

The following table shows the 15 minor keys, with their corresponding key sig-

natures and scales.

The 15 Minor Keys

Same as This

Scale Notes Major Key

A minor C Major

A-sharp minor C-sharp Major

B-flat minor D-flat Major

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How can you quickly determine which key signature you’re looking at?

It depends on whether the key signature contains sharps or flats.

If the key signature includes flats, the key (no pun intended) is to look at

the next-to-last flat—the one that’s next to the farthest one on the right.

This note determines the key signature.

For example, if a key signature has two flats, you look at the next-to-last flat and

determine that the key is B-flat, which it is. If the key signature has three flats, you

look at the next-to-last flat, and determine that the key is E-flat. It’s pretty easy.

But what do you do if there’s only one flat? There’s no next-to-last flat! For the key

signature with a single flat, the key is F. You’ll have to memorize that one, as you

will the key with no flats or sharps—which is the key of C.

If the key signature includes sharps, the method is different. What you want to

remember here is that the last sharp in the key signature represents the seventh

degree of that particular scale, so that the tonic of the scale is the next note up.

In other words, look at the last sharp and the next note up is the key.

Take, for example, the key signature with one sharp. That sharp is on the note F-

sharp, so the next note up tells you that the key is G. If the key signature has two

sharps, the last one is on the note C-sharp, and the next note up is D—which is

your key. And so on for all the other sharp key signatures.

Tip