Why have I never found any music written in the key of C Sharp Major?

Question

Music is written in almost every key that corresponds to every note that is on my piano keyboard. There is clearly a C Sharp (black key right of C) on my piano keyboard but I don't recall ever seeing any music written in the key of C-Sharp Major.

Surely the key of C-Sharp Major must exist! So why is it never or rarely used?

Are there situations where the key of C-Sharp Major would be more appropriate than say the key of D Flat Major?

EDIT: I never meant to suggests that you can't find examples of music written in C-Sharp major on Google (as Todd Wilcox pointed out in his comment). It's that it is comparatively rare and I don't find it in any of my many music books among many thousands of songs.

Answer 1

C sharp major has seven sharps, D flat major has five flats. Out of the box, the latter is preferable. The former may be more appropriate when there is more material requiring "flattening" the key signature than otherwise. Now major is a rather sharp mode, so it's not quite unlikely. For example, a "proper" fully diminuished chord in C sharp features C-sharp, E-natural, G-natural, B-flat. The same in D flat is D-flat, F-flat, A-doubleflat, C-doubleflat. If we are talking about the "functional" dominant seventh (G#7, namely G#, B#, D#,F#) replacement, it's actually D sharp dim (D#, F#, A, C) with its enharmonic cousin E flat dim (Eb, Gb, Bbb, Dbb). The former has a lot more reserves for modulation than the latter.

Answer 2

Yes indeed there is a key of C Sharp Major (C# Major). But the key of C Sharp Major is the “enharmonic equivalent” of the key of D Flat Major.

What that means is that all of the notes in the C sharp major scale sound pretty much exactly the same (to the human ear) as all the notes in the D Flat major scale – only they are notated (written) differently.

The black key to the right of any C key on a piano keyboard is in fact a "C-sharp" and will be most likely be referred to as such when playing a piece in any key that contains a C sharp in the scale or in any key with sharps in the key signature for that matter. But the exact same black key can also be identified as a D flat – and will be referred to as such in pretty much any key with flats in the key signature (with occasional exceptions).

So it may be helpful to understand that on any keyboard instrument (such as piano) or fretted instrument (such as guitar), the notes played in the D-Flat Major Scale will be exactly the same as the notes in the C-Sharp Major scale.

Therefore – given that a particular melody or arrangement of note pitches can be written either as D Flat Major or C Sharp Major and will be played on the same keys or frets either way (and sound the same), most composers will choose D Flat because instead of seven incidentals (7 sharps) to deal with in the key signature for C Sharp Major, there are only five incidentals (5 flats) in the key of D Flat Major.

However, in a case where a musical composition were to modulate (change keys) from another key containing sharps in the key signature, it might be more appropriate to use C Sharp instead of D Flat.

The foregoing also applies to the key of C Flat Major as well - which is the enharmonic equivalent of B Major – only in C Flat Major there are seven flats in the key signature compared to five sharps in the key of B Major.

Interestingly the key of C Flat Major is the only case where the enharmonic equivalent of a Flat key is a Natural key.

Also interesting to note is that the C-Flat Natural Minor Scale contains three double flats in addition to four regular flats (quite cumbersome to notate in a key signature to say the least). Whereas the enharmonic equivalent B Natural Minor scale only has two sharps – yet contains the same note pitches in the same order with the same intervals and sounds the same. But it’s obviously much easier to write.

So given a choice between notating a musical composition using a key that includes 7 incidentals (sharps or flats) in the key signature versus notating the same note pitches using a key with only 5 incidentals, most composers will choose the one with only five (in most cases)!

Answer 3

The other upvoted answers here are good and I don't want to repeat them, but I think that there is a lot to add.

Surely the key of C-Sharp Major must exist! So why is it never or rarely used?

There are several factors that need to be taken into consideration. Here I list a few:

Historical

To understand modern scales you need to look at how they originated. This can be fairly technical so I will give the short version. Before the major/minor system there were hexachords - scales built from 6 pitches with 1 tone steps except for a semi-tone in the middle, 3-4. In the Middle Ages, music used 3 hexachords:

• hexachordum naturale: C D E F G A (semitone in E-F)
• hexachordum durum: G, A, B♮, C, D, E (semitone in B♮-C)
• hexachordum molle: F, G, A, Bb, C, D (semitone in A-Bb)

In the 15th century or so more hexachords were added using the same process which results in sharps and flats being added one by one. Eventually, you could have one that looks like this: C#, D#, E#, F#, G#, A# (semitone in E#-F#). It's a bit like the circle of fifths in equal temperament where you add a sharp (flat) for each modulation up (down) a fifth.

Note that in these eras there is no equal temperament yet, so C# and Db hexachords (or even major scales) do not sound the same. In general, I will consider equal temperament when answering your question.

The point is that not all scales were treated equally. Those with less accidentals had historical preference and it took time until those with more accidentals were "discovered" and used. And we all know that old standards stick and have heard at some point the answer: "because of historical reasons".

"Color" and meaning of a scale

This is a bit more fuzzy. There were (are?) notions of different "colors" and meanings for scales.

"Color"

You might have heard things like "F major is very bright [compared to, say, Bb major]" or "C# minor is very dark [compared to A minor]". It could be that this was the acoustic result of the tuning system and instrument building at the time (remember that the instruments evolved with the expansion of hexachords, so before the 14th century instruments didn't need/have a D# pitch, for example).

Meaning

Sometimes different scales mean or symbolize something for composers. You sometimes hear "Beethoven chose insert scale here because it was associated with freedom [or something]". For example, Beethoven saw C minor as "powerful and emotionally stormy".

It will require digging to figure out what each scale was associated with at each musical era or for different composers. I have yet to see any such association/symbolism for C# major, nor a "color".

The scale in which we hear

Again, this topic is a bit fuzzy, but I will make my point clear. Most (all?) of us, when we compose music in our heads, do it in one of just a few scales. Try to compose a few tunes in major and minor on different days (don't listen to anything tonal beforehand) and be faithful to the key you hear them in. You "should" find out that you don't hear the music in your head in 10 different scales - you stick to a few.

I'm not sure what kind of bias it has or what the statistics are. I'm just noting that, again, not all scales are treated equally.

Ease of use

Scales with less accidentals are easier to read and play. It's also easier to modulate around them. Just as an example from A-sharp minor: "A♯ major, usually replaced by B♭ major, since A-sharp major's three double-sharps make it impractical to use." I wouldn't take Wikipedia as a gospel, but "impractical to use" is somewhere in the right direction. Nevertheless, Chopin modulates to A# major in one of his pieces.

Both C# and Db major have a lot of accidentals.

Conclusion

Any combination of the above can give you the answer. There are certainly many instances where those keys are used, either as the base of the piece or in a modulation, but they are truly less abundant than the scales we usually see (hear). Just remember that C# major is not the scale with most sharps as you can always take enahrmonic scales like A# major and these are used even less.

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Are there situations where the key of C-Sharp Major would be more appropriate than say the key of D Flat Major?

While the previous question would be more in the area of musicology, this one is much more technical and one has to look at theory. I won't go deep, but the answer is "yes". Here is a simple example:

You write a piece in Binary form in F# major. You modulate to the fifth, which is C# (not Db) major. You then modulate back to F# major and finish the piece. This is a regular I-V-I form.

Answer 4

one reason could be - especially for brass instrument arrangements:

Cornets, Flugelhorns, Baritones, Trombones are tuned in Bb, Tenor Horns (Alto-instruments) in Eb. Bass in Bb and Eb. Mind that they have already to read with 3 sharps while other instruments in C have no signs ...

Why didn't Bach notate the C#-prelude in Db?

I would prefer to read the first page in Db major but near the end as it modulates to c# minor there there are some chords: e,c#,a,f#,d#,b# this would be Fb,Db,Bbb,Gb,Eb,C and more difficult for reading and analyzing.

a propos analyzing: This is a lot easier in C# major - as you can drop all signs (7 sharps and read it in C major and understand it much better.

btw. there's actually a transposition in Db on the IMSLP

Answer 5

Shorter answer: Every note in a scale must be named A, B, C... etc. in ascending order but with as many accidentals like sharp and flat as necessary.

Therefore, the note before C# (major 7th) is B sharp (the same as C natural), and E# (same as F natural) is the third which is annoying to work with.

Answer 6

Im a violinist and guitarist, so I find C-sharp to be easier than D-flat on this instrument. My best friend is a pianist, who prefers D-flat. Same with one of my other harpist friends, who prefers D-flat unanimously, because C-sharp just doesn't go well with the harp (neither does d-flat tho :/). HOnestly, I think that the gap in use just depends on the kind of instrument you use. Guitar and violins tend to find playing in c# major easier than Db, while the opposite goes for piano and harp.