J.C. Bach's keyboard works include several sets of accompanied sonatas, a genre that enjoyed a wide popularity during the Classical era, but never found its way into the concert repertoire. The accompanied sonata was a genre meant for domestic performance; the solo keyboard sonata, on the other hand, was adopted in due course by concert audiences. J. C. Bach composed works within both genres during most of his productive years, and his output constitutes a corpus of remarkable consistency. J. C. Bach's removal to London in 1762 coincided with his clear adoption of a galant style, marked by the Italianate influence, and the abandonment of most Baroque traits. The British milieu provided additional factors: the rise of the pianoforte, a thriving music-publishing market, and a great interest in domestic music making among the affluent classes. These factors marked J. C. Bach's output at various levels. Keyboard works had to conform to the proficiency of the amateur performer, a fact reflected in the accompanied output mostly. The number of movements, their length, and the inclusion of particular technical devices are readily observable differences between the two genres. The most remarkable distinction lies perhaps in the preference for binary sonata format in the accompanied. sonatas from the mid 1760s to the 1770s, in spite of a later tendency for tripartite designs in both genres. J. C. Bach's lifelong preference for motivic phrase structure conditioned his keyboard production and partly explains the gap in quality between some of his works and sonatas composed around the same time by Haydn and Mozart, who developed more effective means to connect the melodic material to higher structural units. J. C. Bach's influence, however, endured in Mozart's handling of melody, and his keyboard production constitutes, in spite of some flaws, a noteworthy example of elegance and craftsmanship.