Why Is There No D# Major Scale

Hey great question!

Good news! Your intuition isn’t wrong. There is a \(D\sharp\) major scale. It does exist, it’s just… not useful. This is where enharmonics shine. I’ll try to illustrate why.

The \(D\sharp\) major scale would be as follows (following the pattern):

\[D\sharp\ E\sharp\ F\sharp\sharp\ G\sharp\ A\sharp\ B\sharp\ C\sharp\sharp\ D\sharp\]

As you can see, every note has a sharp and \(C\) and \(F\) even have double(!) sharps. There’s also the fact that \(E\sharp\) is simply \(F\) really, but due to theory we notate it as \(E\sharp\) nevertheless, there’s also \(B\sharp\), etc., etc. Maybe you can kinda see why it could be less than ideal to deal with a scale like this.

Now, while this is an actual scale and is completely valid, reading music written in this key can be quite uncomfortable especially considering there’s a perfectly valid alternative.

What’s the enharmonic note for \(D\sharp\)? It’s \(E\flat\). Its major scale would be:

\[E\flat\ F\ G\ A\flat\ B\flat\ C\ D\ E\flat\]

Now this seems much more reasonable. We only have 3 flats and reading it should be completely fine. Key signature is much more simple to grasp and it’s just more straightforward to deal with \(E\flat\) instead of \(D\sharp\).

You’ll learn more about reading and key signatures later on in the course, but I hope this helped explain why some people might just say “there’s no X scale” to simplify things.

NOTE: This post was copied from a response I wrote years ago on the Coursera forums.