When describing music, sometimes it makes more sense to use sharps and sometimes it makes more sense to use flats. For instance, if we called the key of B flat by its enharmonic equivalent A sharp, there would be 10 sharps in the key signature. Since B flat only has two flats, it makes much more sense to use the key of B flat rather than A sharp.
It's crazy to think that I've been teaching music for almost 20 years. In that time, I've had the privilege of helping hundreds of people get started playing guitar and also improving on the guitar skills they already have. It's funny how often a lot of the same questions are asked over and over.
One of these recurring questions goes something like this, "why do some notes have two names? Why is A# also called Bb? Why don't we just pick one???"
This is a valid question! For someone who is dipping their toe into the ocean of music knowledge, this can be an annoying extra bit of information to deal with.
Check out the circle of 5ths diagram below:
If the circle of 5ths diagram is new for you go to the following link to learn what it is and how it can be used:
How do I use the circle of fifths???
Notice how the key of C has no sharps or flats. As we move clockwise, each key gets another sharp. Once we make it to the key of F# there's an option to use the key of Gb instead.
Since the key of F# has 6 sharps it's possible that a composer may choose to Gb which has 6 flats. The keys of F# and Gb both have the same number of accidentals. The composer can choose which one of those keys best suits her purposes.
Continuing to add more sharps just becomes awkward. It is much easier to use the flat keys. By the time you get to A# there are 10 sharps in the key! Who would want to keep up with that. Conversely, Bb has just 2 flats. Check the examples below:
The notes in a Bb major scale are: Bb, C, D, Eb, F, G, A, Bb
The notes in the enharmonic A# scale are: A#, B#, Cx, D#, E#, Fx, Gx, A# ("x" stands for Double Sharp. Yes, that exists.)
To be clear, both scales would be played exactly the same way on the guitar or any instrument.
It would be ridiculously cumbersome to use the key of A#. The same would be true if we used a flat key where it would make more sense to use a sharp key, i.e. the key of Fb instead of E.
What's the big takeaway? If you're just starting out, call the notes whatever you want. As you become aware of the keys that you're playing in, try to name the notes correctly based on the key of your music. Get a qualified music instructor who can clarify this more as you move forward.
Why is all the music for my instrument written in the same two or three keys?
Some instruments are better suited to play in some keys rather than another. For instance, based on the way it is tuned, the guitar generally has an easier time playing in sharp keys like G, D, A, E, and B.
Vice versa, wind instruments like the trumpet generally have an easier time playing in flat keys like F, B flat, E flat, A flat, and D flat. If you'd like to understand why this is go to the following post: link to blog post about "Why do guitarists hate flat keys."
I hope this makes sense. If you have more questions contact us here: