Introduction: How to Read the Key Signature (quick Way)
It is often frustrating starting a new piece and finding yourself stuck before you play any note, trying to figure out the key signature, the major or minor scale and the fingering.
This is especially true for beginner musicians but not exclusively.
Thankfully there are a few easy tricks and a secure method to figure out quickly the key signature and all the above.
First of all, you probably have already learned in your music lessons that C major has no flats and no sharps. This is taken as a given, and it will help you understand the following.
The Series of Sharps and Flats
First of all, you must know the series of sharps and the series of flats by heart.
The raw method is to remember that the sharps appear in this series: #F-C-G-D-A-E-B and the flats in this: ♭B-E-A-D-G-C-F
This means that if you only see one sharp, it will be the first one (F#), if you see two, the first two (F#, C#) and so on.
However! there is a trick to remember these series, which is the following mnemonic for the sharps: #Father-Charles-Goes-Down-And-Ends-Battle and for the flats: ♭Battle-Ends-And-Down-Goes-Charles'-Father
Following the initials, you can easily find the sharps or flats of the key signature.
e.g. Two flats, the first two words of the mnemonic for the flats are 'Battle-Ends'. So B♭ and E♭!
Finding the Scales Now that we can recognise the key signature, we have to see the scale that they indicate.
For Major Scales:
Sharps: For scales with sharps (all the scales which do not start with a flat, except F major) we have to locate the Leading Note.
The Leading Note is the seventh key of the scale, always one semitone before the tonic, first note of the key. So for C major, B is the Leading Note, for G major, F# is the Leading Note and so on.
The last sharp of the key signature is the Leading Note of the scale!
e.g. 3 sharps: Father-Charles-Goes (F-C-G), G# is the leading note of A major! So A major has three sharps
To find the key signature of a scale, you must invert the method.
e.g. B major, Leading Note is A#, so the key signature includes all the sharps up to that: Father-Charles-Goes-Down-And. So B major has a key signature of 5 sharps (F# C# G# D# A#)
Flats: For scales with flats (all the scales which start with a flat, plus F major) the method is quicker, but we have to be more careful.
The penultimate flat in the key signature is the key.
e.g. 3 flats: Battle-Ends-And (B-E-A), E♭ major is the scale!
To find the key signature of a scale, you must invert the method. Therefore, you must add a flat, after you locate the key in the series.
e.g. D♭ major. We must locate D♭ and add one more sharp, so Battle-Ends-And-DOWN-Goes. So D♭ major has a key signature of 5 flats (B♭ E♭ A♭ D♭ G♭)
EXEPTION: Since you cannot locate F natural on the key signature (only F flat), you must remember by hear that the scale of F major has one flat: B♭.
For Minor Scales:
Every key signature corresponds to two scales: one major, one minor.
These two scales are called Relatives.
To find the Relative Minor, you must go a minor third down (3 semitones) from the Relative Major.
e.g. C major - A minor, G major - E minor, B♭ major - G minor and so on.
So, to find the Minor Scale that a key signature belongs to, you must first find the Relative Major and then move down a minor third to the Relative Minor.
e.g. 3 flats: Battle-Ends-And, E♭ is the penultimate flat and our major scale. One minor third down from E♭, it is C. Therefore, C minor has three flats (B♭ E♭ A♭)
This is the easiest to explain and the hardest to achieve.
Practice. Practising the scales is the best way to memorise the fingerings that you must use, regardless of the instrument that you are playing.
In the beginning, it might be challenging, but it is guaranteed that by practising the scales daily, the fingers will automatically know where to go.