Mozart Violin Sonata in Bb K378: Transcribed for Cello

Of the 17 Mozart violin sonatas presented on this website in version for cello, only two have been transposed down from their original key in order to make them more playable. This K378 sonata is one of them (the other is K454). In both cases the transposition is down a minor third, which gives us the double advantage of simultaneously lowering the register and removing three flats from the key signature. In this sonata, we thus go from the original Bb major into G major (Eb to C major for the slow movement).

It’s a shame that so much of this sonata lies so awkwardly in its original key (try it – the original key transpositions are also available on this page), but in fact the transposition down is not particularly problematic. With electronic pianos the original piano part can be used with the “transposition button”, but on normal pianos we don’t have this possibility. Therefore the piano part has been rewritten here in the new key. This transposed piano part might pose a problem for those pianists who already know the sonata (for whom it will certainly be confusing to learn/play it in two different keys). The rewriting of a piano part is more laborious than the rewriting of just a cello part, but when the reward is making such a wonderful sonata – probably one of the most beautiful in the Aladdin’s cave of Mozart’s violin sonatas – suddenly and definitively playable on the cello, then that rewriting effort was certainly worthwhile!

FIRST MOVEMENT: Allegro Moderato

What an extraordinarily beautiful movement this is: the diamond on the crown of the royal jewels? In bars 75 and 150 the lower notes of the doublestops have been transposed up an octave to get them out of the elephant register. Apart from this revoicing, no other note changes have been made for the adaptation of this movement to the cello.

In the “Easier Version”, some entire high passages have been transposed down an octave but at other times, to avoid having to transpose down an entire passage just for one or two isolated high notes, those individual notes have been transposed down an octave or substituted for other notes. In fact, the difficulties (substantial) of this movement come more from the fast semiquaver passages than from high-register playing and quite a few isolated note changes have been made to make the fast passages easier. This “rewriting” was considered the least unsatisfactory of the possible simplifications.

The page layout is problematic because of the combination of the movement’s length (it’s a biggie) with the need for compatibility between page turns and repeats. So the music is quite spread out across four pages, with a comfortable page turn between the two main sections. We can use this as an experiment to explore just what psychological effects it has on us to read music that is written out in a very wide, spacious format. It’s a little like reading a book with large print – it can feel childish, but does it perhaps make us more relaxed and expansive, and is it easier to assimilate the information and read “ahead”?

  1.  Edited Version
  2.      Clean Version
  3.      Easier Version
  4.       Literal Transcription
  5.      Original Key
  1. Piano Score

Here are two downloadable audio play-along piano accompaniments, with thanks to the Violin PlayAlong YouTube channel. The first is a little slower. Both have a one-bar introduction so that we can know when to start playing:


SECOND MOVEMENT: Andantino Cantabile e Sostenuto

It is above all the first and third movements of this sonata that really need the lowering of the register (key). The slow movement, by contrast, doesn’t benefit at all from being transposed down as it already lies in a very low register. In fact it becomes so low in the new key that large chunks of it sound quite awful: now we are really in the cello’s “grunting” register (instead of its singing register)! So what can we do? We can’t play this movement in it’s original key if it’s sandwiched between the two outer movements that have been transposed down ….

Well, surprisingly, the transposition down a minor third brings us so low that we can actually retranspose all those grunting sections up an octave, which brings us into the cello’s singing register where it actually sounds wonderful, without being so high that it might become difficult! So, in this cello version, bars 1-24 and 38 to the end (more than 2/3 of the piece) are played at the same pitch as in the original violin version (but still transposed down a third). This is now way better even than the original key version. Apart from these octave transpositions, no other notes have been changed.

The movement gets off to a slow start, sounding quite simple and childish at first. But from bar 16, where the piano changes from languid triplets into the intense pulsating semiquaver accompaniment figure, the music is suddenly transformed into a wonderful lyrical mature outpouring of expressive beauty. The double bar which separates these two sections is like a magic door which opens onto an enchanted paradise, or alternatively a magic wand, which miraculously transforms the sleepy caterpillar into the most gorgeous butterfly…..

  1.   Edited Version
  2.      Clean Version
  3.      Easier Version
  4.      Literal Transcription
  5.       Original Key
  1.  Piano Score

Here is a downloadable audio play-along piano accompaniment, with thanks to the Violin PlayAlong YouTube channel.



No notes at all have been changed in this sparkling Rondo movement in which there are only a very few high passages needing transposition for the “Easier Version”. Most of the difficulties come from the tricky bowings, especially in the 12/8 spiccato second section.

  1.    Edited Concert Version
  2.          Clean Concert Version
  3.         Easier Version
  4.          Literal Transcription
  5.       Original Key
  1.   Piano Score

Here are two downloadable audio play-along piano accompaniments, with thanks to the Violin PlayAlong YouTube channel. The first is a little slower.