Key signatures are the symbol of the raw materials that a piece of music is constructed. This gives us valuable information to know which harmonic journey. Knowing in which key is a piece is especially useful for piano students as the instrument is essentially harmonic.
It should be the responsibility of all piano tutors to explain and ask every time a student starts studying a piece in which key signature the music is.
This task is sometimes tricky to find out. It frequently happens that the student already knows in which key just by the experience of playing the scales. Still, in Romantic of contemporary repertoire, sometimes we find “difficult” keys with more than five sharps or flats, and then the problem starts.
For that reason, Georgios Kommatas wrote an article to explain how to spot them quickly and easy.
For example, there is a simple way to memorise the order of the flats or sharps with the aid of a mnemonic:
For the Sharps:
#Father-Charles-Goes-Down-And-Ends-Battle
And for the Flats:
?Battle-Ends-And-Down-Goes-Charles’-Father
There is another “trick” to know in which key is a piece, as Georgios says in his article:
For the keys that have sharps:
The last sharp of this Key Signature is the ‘Leading Note‘ of the key.
The Leading Note is the 7th note of every Scale, and it is always one semitone under the ‘Tonic‘, the first note of the key.
For the keys that have flats:
The penultimate flat in the key signature would be the key.
Through with method, now we can know where are we harmonically, at least for the Major keys. Now, what happens with the minor ones?
“Find the relative major and then move down a minor third to the relative minor.”
This, of course, is not the end of the journey, that the beginning!
Once we know the basic structure, our decisions towards the piece will be more precise and more substantial than before.