The System of Key Signatures
Key signatures use a specific system. Not just any note can appear in a key signature. There is an order and a logic to key signatures that makes them understandable. Key signatures appear in two varieties: sharp key signatures and flat key signatures (excluding C major, which has no sharps or flats). A key signature will always display only sharps or only flats. You will never see both in the same key signature. Within the groupings of “sharp keys” or “flat keys,” there is an order to how individual notes appear. Take a look at sharps and flats separately.
Just like proper scale spellings will result in either sharps or flats, key signatures follow the exact same rule. They do so because scales and key signatures are showing you the same information, which is exactly why they help you understand more about the music.
Sharps appear in key signatures in a specific order. Here is the order of sharps as they appear in key signatures: F#, C#, G#, D#, A#, E#, B#.
The sharps always follow that order. Also important to note is that sharps appear in the same order. If the key has one sharp, it will be an F#. If the key has two sharps, it will have F# and C#. It always works through the pattern that way. A great way to remember the order of sharps is to use a little mnemonic device: Father Charles Goes Down And Ends Battle. The first letter of each word corresponds to the sharps as they appear. It's silly, but it might just help you remember.
Point to Consider
Even though key signatures may appear confusing at first, most musicians would have a hard time reading without them. Constant flats and sharps placed throughout music can be more challenging to read than a single key signature.
Just like sharps, flats appear in a specific order as well. Also just like sharps, the order of flats will also appear in the same order every time. Here is the order of flats as they appear: Bb, Eb, Ab, Db, Gb, Cb, and Fb.
There is also an easy way to help you remember the order of flats: Just reverse the saying for sharps! Battle Ends And Down Goes Charles' Father. One saying gets you both sharps and flats — pretty convenient!
If you stare at the circle of keys long enough, you might memorize what each key represents. There are a few tricks that can help you out. On the flat side, the first key is F, which starts with the same letter as the word
For any key that has a sharp in it, naming the key is as simple as following two easy steps. First, find the last sharp (the one all the way to the right). Once you've found and named the note that corresponds to the same line or space the sharp is on, go one note higher, and you've named the key. Look at FIGURE 5.4. The last sharp in this key is A#. Going one note above this is the note B. Five sharps is, indeed, the correct key signature for the key of B major. You can check the trusty circle just to make sure.
The good news is that this works on every key that has a sharp in it. To find the name of a sharp key:
1. Name the last sharp, the one all the way to the right.
2. Go one note higher than the last sharp, and that's the name!
Easy enough! Unfortunately, it works only when you're looking at a key. If someone asks you, “How many sharps are in the key of E major?” this little trick won't get you very far. For everything else, refer to the circle of keys and the order of sharps and flats.
The flat keys have their own, different trick for naming them. When you see a piece of music that has flats, find the second-to-last flat. The name of that flat is the name of your key! This is an easy one. Look at the example in FIGURE 5.5. This key has two flats and the second-to-last flat is Bb. The name of the key with two flats is Bb! This one is an easy trick.
There is one exception, however: the key with one flat, F major. Since this key has only one flat, you can't find the second-to-last flat. In this case, you'll just have to memorize that F has one flat (which is Bb). Shouldn't be too hard! To find the name of a flat key:
1. Find the second-to-last flat (from the right).
2. The name of the flat note you find is the name of the key.
Just remember the exception — the key of F major has one flat and therefore the rule does not work for it. For the other keys, it works like a charm!
The name of this section says it all! The circle of keys is often referred to as the “circle of fifths” or the “circle of fourths.” The keys are arranged in the circle in a fairly logical way. The key of C, with no sharps or flats, sits squarely in the center, and the sharp keys move around the right side, each key increasing the number of sharps by one. The flat keys move to the left, increasing their flats by one as they progress.
Even before you learn the entire circle of fifths by heart, you can construct it using intervals. Draw a C at the top of a piece of paper. Now draw a few fifths to the right to name the sharp keys. To the left, draw a few fourths to get your basic flat keys. Across the bottom of the page, spell the order of sharps from F, in fifths, and the order of flats from B, in fourths. As you move away from the key of C, each key increases by one flat or sharp (depending on which direction you move in). You can match up the flats and sharps from the bottom of the page.
If you move to the right from C, each key is exactly a perfect fifth apart! Not only that, but the order of sharps as they appear in the key signatures are also perfect fifths starting from F#.
If you move to the left from C, each key is exactly a perfect fourth apart! Conveniently, the flats as they appear in the key signature are also a perfect fourth apart, starting from Bb.
Think about these two points:
Sharp keys move in fifths around the circle, and the order of sharps are fifths apart.
Flat keys move in fourths around the circle, and the order of flats are fourths apart.
Note that when you move in one direction in the key circle, you move in fifths, and when you move in the opposite direction, you move in fourths. Remember the explanation in Chapter 2 about interval inversion: A perfect fifth becomes a perfect fourth when inverted. A fifth up is the same as a fourth down. The same applies to the order of sharps and flats. The sharps are spaced a fifth apart starting from F, and the flats are spaced a fourth apart starting from B. Interestingly, when you spell out all the sharps and read them backward (backward = inverted = in fourths), you get the order of flats.