About this work
Published in 1739 at the end of the third Clavier-Übung (Keyboard Practice), his monumental compilation music for harpsichord, the Duetto (4) of Johann Sebastian Bach (1675-1750) are basically more elaborate two-part inventions. The third Duetto in G major, BWV 804, like the second in F major, is in embryonic sonata form with the outer sections in the tonic major functioning as exposition and recapitulation and the central section modulating through minor keys functioning as the development. Over a walking bass line in the left hand, the right hand first states the theme, a lyrical melody in short phrases. The left hand takes the second statement of the theme in the middle of the keyboard while the right hand spins out the theme as embellishments at the upper end of the keyboard. The left takes the third statement of the theme at the bottom of the keyboard while the right hand continues to spin out embellishments. The central development moves to the minor and climaxes with the theme stated in the minor in the left hand at the bottom of the keyboard. After a transition through imitative entrances of the theme in both hands, the theme returns in the tonic in the right hand at the top of the keyboard and the work closes with the theme once again in the left hand at the bottom of the keyboard and once again in the tonic major.