For a beginner musician, one of the most difficult and confusing topics is the topic of determining and building a key. In fact, it is enough to learn a few rules to easily and easily navigate both the major and minor keys.
Major scale
If you have already started to study solfeggio, then you know that any major key is built as follows: tone - tone - semitone - tone - tone - tone - semitone.
The defining tonic is the first note of the first degree. If you use the key in C major, the key will be the note C. For clarity, you can consider an example of the key in G major. The first step is G-la, move up from the G note in the indicated order:
Salt-la - tone
La-si - tone
Ci-do - semitone
Do-re - tone
Re-mi - tone
Mi-fa # - tone
Fa # - salt - semitone
So, you got the key of G major with one sign (sharp - #) with a key with the following scale: G - A - B - C - D - E - F # - G.
If you start building keys in this way, moving up by fifths, you will get 6 more keys:
1. D major - 2 #
2. A major - 3 #
3. E major - 4 #
4. B major - 5 #
5. F sharp major - 6 #
6. C sharp major - 7 #
However, to determine the number of characters with a key in a particular key, you do not need to constantly build a scale in accordance with the rule of seven steps, it is enough to remember the order of sharps, which never changes:
1. Fa #
2. Before #
3. Salt #
4. Re #
5. La #
6. Mi #
7. C #
So, if you take a key with three sharps, it will be F #, C # and G #. If with two, then fa # and before #. Another important rule is that the tonic in the major scale is the next highest note in the octave after the last sharp in the key. If you have three sharps - F #, C # and G #, then the tonic will be the note A, and the key, respectively, will be in A major. Thus, when you need to determine the number of characters in the key of any key, it is enough to take the previous sharp note descending in the octave and determine its ordinal number in the series of sharps. For example, you are asked to determine the number of sharps in the key of E major. The previous note is re #. In the row of sharps, it occupies the fourth place, which means that there are four characters for the key - re #, salt #, before # and fa #.
Minor scale
If you have already figured out the key signs of the major keys, then it will be much easier to figure out the minor ones. There are parallel keys. These are major and minor keys with the same key signs. The distance between them is one minor third down from the minor tonic. In other words, to define a parallel minor key, move three semitones down from the major key.
Memorizing the correspondences between major and minor keys is not necessary, over time it will settle in your head by itself. But to learn the order of flats to determine the signs and their number with the key is worth it.
So, the order of the flats is as follows:
1. C
2. Mi
3. La
4. Re
5. Salt
6. Before
7. Fa
Flats are counted in the same way as in major keys, only the tonic rule is different here. The major tonic is not the next note, but the penultimate flat of those given in the key. That is, if you take a tonality with four flats (si, mi, la, re), then the third of them (aka the penultimate one) - la - will be the tonic. This gives you the key of A flat major. Using the three-flat rule, you get the minor tonic in F and the key in F minor.
