Violin - Slurring double stops

Question

I was reading some violin sheet music when I came across something that looked like a slurred double stop. Here is an image:

The problem is that both double stops use the same fingers, but on opposite strings. Assuming first position, the first double stop uses second finger on D string and first on A string, and the next note uses first finger on D string and second on A string.

How can you move both fingers to other strings, under a slur, without playing a little bit of open strings?

Answer 1

You have several options depending musical context.

• The best thing is to see this challenge coming and prepare by putting your first finger equally on both D and A strings, as if you were playing a double stop of a fifth, the E on D string and the B on A string. (Note, this is very different from a fretted-instrument "barre" technique, since your finger is still oriented as normal, not at all "sideways.") Then you only have to move your second finger.
• Your second finger can switch strings quite quickly, but you still want to avoid sounding that "E/B" fifth that your first finger is responsible for, even for the millisecond that your second finger moves. If the musical context is appropriate, you can simply use a bit of portato in the bow, slowing or stopping ever so slightly at the moment of transfer. If not, you can momentarily rock the bow away from D string as your second finger moves, so that for a split second you're bowing only A string, and then return the bow to D string as your second finger lands. Since the A string sustains throughout, the listener won't notice any "stoppage" in the sound and it will be perceived as a seamless slur.
• This example isn't the most conducive, but you can often avoid the issue by shifting during the slur. For instance, if you started the slur in fourth position (using 3rd and 2nd fingers on G and D strings), you could shift on the second note to fifth position. Your 2nd finger simply slides up D string, and the G string note changes from 3rd to 1st finger; no finger has to switch strings. For this particular pair of notes it's a bit hard to imagine why you'd be up in fourth position in the first place, but for other similar scenarios a shift could be convenient, especially if the audible slide is expressively appropriate.

Answer 2

You don't write the key signature, but even assuming it is C major, you can play both low notes with the index finger (pressing down on both strings in what guitar players call barré) while changing from ring finger on the D string to middle finger on the A string. That allows reasonably uninterrupted notes.

Some composers treat a violin like a guitar (or a lute or a viol, depending on the historic frame) and sometimes it is an advantage for a performer when they happen to have some experience across the aisle that was a lot less pronounced in early string instrument history.

Or like an advanced piano player: don't think in terms of fingerings but rather of notes, and whatever finger can be brought over conveniently to do the job is responsible for doing it. In terms of reliable intonation and fast runs, fixed positions and fingerings are a strategic advantage for playing, but sometimes the music does not leave the leeway for using those aids.