Why is music for strings more likely to be in keys with sharps?

Question

One thing I've noticed is that music written for strings, such as violin concertos, are a lot more likely to written in a key like D or A major than something like F or Bb major. I recently saw a comic that confirms my suspicions:

Now, this does include both major and minor keys; a minor key has three fewer sharps than its parallel major key. But even if we shift over everything by 1 or 2 positions on the circle of fifths (as an average between 0 and 3), there is still a very obvious bias towards keys with sharps. Why does this phenomenon occur?

Answer 1

Sharp-keys are in some ways nicer to play than flat ones.

The preference for these keys is perhaps most extreme in folk styles: going through two collections of celtic-style fiddle music^{[978-1-85720-202-1],[1-871931-04-5]}, I found the distribution to be this crass:

• ♭♭ : 5
• ♭  : 5
• ♮  : 7
• ♯  : 57
• ♯♯ : 70
• ♯♯♯: 9

In particular D major is really a great favourite. In fiddle playing, this is also easy to explain: you want to use empty strings much more than in classical music. With more than two ♭s that's simply impossible on the high violin strings, but even for B♭, F, and C major the empty strings occur mostly on thirds. That is problematic, because these notes are the ones you need to do most intonation-adjustment on (upwards for leading notes, down for chords/double stops). In D major OTOH you have the fundamentals of the primary chords on the empty strings, which is perfect for droning etc.; while the thirds are all fingered and can be moved as necessary.

Now, empty strings are somewhat shunned in much of classical music, but in particular for solo playing (think the Bach Cello Suites!) they also have quite a significance. These are actually something of a counterexample though, with both Suite IV and V featuring 3 ♭s. However, since it's totally solo, you can much better "cheat": instead of adjusting the thirds, you adjust everything around them...

Otherwise, it's certainly a bit of a self-fulfilling truth: because the simple tunes are mostly in those keys, those are best practised, hence even advanced players may be a bit more firm in them than in ♭-heavy keys.

Answer 2

The answer is a relatively simple answer: it is easier for the violin an cello to play in those keys because of how the strings are configured. Look at this picture of a G scale on the violin:

As you can see, the G major scale fits very nicely on as the open strings notes make the scale extremely easy. Also because of the open string notes, many other sharp keys are easy to play like C, D, and A. It is also easy to use G#, D#, A#, and E#(F) because they are easy to grab because they are right next to the nut on the fingerboard. When it comes to flat keys, they can be played on the violin and cello, but they lose open string options. For example, if you were playing in Ab major, the only open string you could take advantage of is G because Ab major contains Ab, Eb, and Db.

Answer 3

For stringed instruments such as the violin, playing in sharp keys (more accurately, 0 to 4 sharps) means making multiple main notes of the tonality coincide with open strings. This amplifies the instrument's show-off potential in two ways:

1. In fast passages, fingering is simplified because any time the melody touches on one of the four open strings, nothing needs to be fingered. Likewise for passages of triple and quadruple stops.
2. In expressive melodic passages, the sound is enriched by the open strings vibrating in resonance with the melody. For instance, play an A on the D-string of the violin (with a bit of vibrato if you like). You will see the A-string start to vibrate. Likewise, if you play a D on the A-string, the D-string will resonate (at its second partial) and the G-string will also resonate (at its third partial). These resonances linger slightly after a different note has been stopped on the original string and help to connect one note to the next.

D minor also works nicely for violin music in this regard (consider Bach's famous Chaconne from Partita no. 2). B minor also works, hence the three data points at B.

Answer 4

On the acoustic guitar, the chords with the most open strings simply sound better and ring more beautifully. Because of this, the most beautiful chords on the guitar are E, A and G. As tonics, those are all sharp keys. E and A have a further advantage: they are often used together in songs because E is the dominant chord of tonic A, and A is the subdominant chord of tonic E. Another chord that happens to ring beautifully is D major as fingered on the three treble strings, and D is the dominant of G while G is the subdominant of D. D is a sharp key also. So many songs for guitar in rock, country and bluegrass are just naturally written in these sharp keys.

Answer 5

The answer is, because for sharps one can re-use the same string as for the natural note and just slide the finger for a half note shorter, so they are significantly easier than flats, where you have to use another string and finger string distance minus one half tone (minor fifth).