Constructing major scales upon different notes within the octave requires accidentals to bridge the gaps that require half steps or whole steps. From the previous chapter we learned that the pattern of steps for major scales is whole, whole, half, whole, whole, whole, half. We also learned that the steps between notes B-C, and E-F are half steps, and the steps between all other sequential natural notes are whole steps.

Therefore, in order to create a major scale on the note G (G Major), the following notes must be used in order to maintain the intervals that constitute a major scale: G, A, B, C, D, E, F sharp, G. The B to C interval is correct with only naturals for the interval between notes 3 to 4, since it is a half step. The F sharp however, must be used in order to make the interval between notes 7 to 8 a half step. As a further example, F Major consists of F, G, A, B flat, C, D, E, F. The distance between A and B is a whole step, but needs to be a half step, hence the B must be altered to B flat.

Instead of writing all of the notes in the piece of music with the attending F sharp or the B flat mentioned above, it is customary to write them once in a key signature. Key signatures provide a convenient way to write music. For example, if the entire piece of music had a hundred F sharp's, you save writing the sharp sign ninety nine times. Accidentals appearing within measures generally signify a note not covered by the key signature. The shape of the different key signatures follow a set pattern, that can be seen in the "Choose Key Signature" window below.

One major and natural minor key share the same key signature. The notes used in each key are therefore the same, the difference is the starting note or tonic of the scale, which is a minor 3rd lower. You will learn more about intervals in the next chapter. The major and minor keys that share the same key signature are known as relative keys. Conversely, Major and minor keys that share the same starting note, are known as parallel keys.

Key signatures imply a scale centered around a main tonic note. Not all music centers around a tonic note, but most music from the last few hundred years does. The key signature for "C Major...or...a minor" implies that the tonic is going to be either "C" for a Major piece, or "a" for a minor piece. How do you know if the piece is in Major or minor? Generally, the piece of music will end on the tonic, so if you go to the very end of the piece, and look at the final note or chord, you should be able to tell.

If you don't know the names of the key signatures, return to the section on naming key signatures in the Elements of Music Notation.

Note: Virtualoso Guitar allows you to change the key signature for all test modes, allowing you to customize your testing to a given set of notes.

Reading left to right, top to bottom, it turns out that the key signatures differ by intervals of perfect fifths. By adding or taking away one accidental at a time from the key signature you change the associated tonic note (or main note) of the scale associated with the key signature. These notes follow a pattern known as the "Circle of Fifths".

By starting at the top note, C, and walking the circle clockwise, you add more sharps to the key signature. By moving around the circle counter clockwise, you add flats. For example, C Major contains a key signature with no sharps or flats. G Major contains a key signature with 1 sharp, and so on. Key signatures that differ by one accidental (that lie next to each other in the circle of fifths diagram), are known as closely related keys.

Note that there are a total of 15 different key signatures, yet there are only 12 unique notes within an octave. The reason for this is that 3 key signatures at the bottom of the circle of fifths use the same pitches as the three other key signatures they are grouped with. Although they use the same pitches, they are using different note names for the pitches, or enharmonic equivalents.

Remember that the notes in each vertical column are enharmonic equivalents, they have the same pitch! This means that these two scales actually use the exact same frets on the guitar even though they are named entirely differently!

Memorize the following note names to the right for sharps and to the left for flats:

(F, C, G, D, A, E, B)

This sequence of names allows you to offset the C Major scale pattern on the guitar to any other pattern. By playing in a key signature with 2 sharps, you will play all of the first two names (F and C) as sharps. By playing in a key signature with 3 flats, start from the right side of the list and work your way in, so you will play the last three names (B, E and A) as flats whenever you see a B, E or A on the sheet music. This is a very useful thing to know since you can navigate the entire fretboard in any key by knowing the pattern of C Major as described in the previous chapter.