It is difficult to talk about keys without some confusion because the physical blocks you strike are called keys. At the same time, it is also necessary to talk about the theoretical keys music is written and played in. For the purposes of this chapter, keys will refer to theoretical keys and not the physical wood piano keys.
Remember the talk about the lounge singer choosing a key in which to sing. Also remember that keys can be major or minor – happy-sounding or gloomy-sounding. There are many factors that determine what makes up the key of the music. They involve theory that is too complex for most beginners.
However, you can learn the key signatures that show what the key usually is. The key signature is a grouping of sharps or flats on the staff at the beginning of a piece of music. There might be no sharps or flats, and if it is a major key, then it is the key of C major. For the purposes of beginning key signature theory, it is best to begin with major keys. The important thing to learn is what notes to make sharp or flat when you are playing.
Write on a sheet of paper: F-C-G-D-A-E-B. Now draw a box around the G. This is a way to remember the sharps and the major sharp keys. One of the sharp keys is G, which has one sharp, which is F. Another sharp key is D, which has two sharps – F and C. In other words, you start with the box to learn the name of the major key. Then, you count the letters starting with G. The key will have that many sharps in it, and they will start with F.
For the flats, write down: B-E-A-D-G-C-F. This time draw your box around the F. Therefore, the key of F has one flat, which is a B flat. Then, you go back to the beginning for the next one. The key of B flat has two flats, which are B flat and E flat.
Before you begin to play a piece, look for the key signature on the left-hand side of the staff after the clef sign. It will simply show sharp signs on each line or space that corresponds with the notes that should be raised one half step. Or, it will show flat symbols on each line or space that matches the notes that are to be lowered one half step.
One thing to remember is that, ordinarily, the sharps or flats in the key signature are carried throughout the piece. That means that, for the key of F, every time you see a B on the staff, you play a B flat, for example. The flat or sharp signs will not be written beside those notes as long as the key signature is in place.
The key signature can change during the piece at any point. If it does, there will be a new clef sign and a new key signature marked on the staff at that point. Another time you might play something different is if you have an accidental. An accidental is a note that is not ordinarily in the key. A sharp or flat sign will be written by it to tell you what to do.
As a beginning player, the key signature is really quite simple. Just use it to tell you what notes to play sharp or flat throughout the piece. You can learn more about keys when you have advanced further in your studies of theory.