Was this skilfully composed work really written during a game of ninepins? The legend persists, although there is no reliable source. At all events the unusual instrumentation is of note: having a clarinet instead of the violin was by all means usual in piano trios; but in addition Mozart replaced the cello with a viola, his favourite instrument by his own admission. As a result the viola has a much stronger part than the cello usually has. Our single edition of this buoyant work was taken from ...