'''Piano Sonata No. 17''' in B flat major, K. 570 (February 1789) is a sonata in three movements:
A typical performance takes about 18 minutes.
The adagio movement (as with the finale, in rondo form) is, in the most part, in three-part harmony.
There is an accompanying violin part of doubtful origin in many 1800 editions; the piano part is exactly the same as for piano solo. Neue Mozart Ausgabe (NMA) hold it as an addition by either André or another. [http://dme.mozarteum.at/DME/objs/ed/ucb20_197_-17.jpg Description at Mozarteum.]